BUILDING A DIGITAL SLIDESHOW -------------------------- John Pazmino NYSkies Astronomy Inc email@example.com www.nyskies.org 2009 December 26
Introduction ---------- At the NYSkies Astronomy Seminars, talks at other astronomy clubs, and presentations at conferences, I am commonly asked about my slideshows. In years before about 2005 there were built from chemofilm pictures -- color slides -- and assembled into a rotary tray for projection. Since the mid 20-thous my slideshows are built from computer images, which is by now almost the only way to offer shows. While i do not take myself to be the master of slideshow presenters, I am credited for giving talks that are highly welcomed, with requests for a repeat in a future occasion. With my own shift to digital photography and computer graphics, I find that my slide shows are vastly more specific for the audience to hand and I have orders greater selection of prime pictures for them. Yet, and this surprises many in the audience, it is indefinitely easier for the lay person to compile a good slideshow with computer images than it ever was with chemophotography.
Slideshows -------- I deal here pura mente with slideshows, a sequential display of still images, like those of the optical-mechanical slide projector. I leave out use of audio and video or interactive techniques here. In spite of the increasing availability and ease of these more advanced techniques, overwhelmingly as at yearend 2009 an astronomy slideshow is a series of still pictures. In the modern means of building slideshows, a slide is just an other computer picture. It doesn't HAVE to hold a picture. It can be a video or audio file. I just as yet didn't need to include such extra bells & whistles in my talks. They are static pictures thru and thru. When the slideshow file is played, you index from slide to slide by a keypress at the computer, similar to working a film-based slide projector. If you prefer, the host can detail an agent to work the computer while you narrate and cue for the next slide. It is common for the astronomer to be at the screen, away from the computer, to better point out features in his pictures.
Presentation software ------------------- Just about every digital slideshow is made in one format, a PPT file that plays with Microsoft's PowerPoint. You can build slideshows with other applications but they will play ONLY with them. For sure they will NOT play on your host's computer. While PowerPoint is THE means of compiling slideshows there is at least one workalike. The free software OpenOffice is a set of business programs parallel to Microsoft Office. The module corresponding to PowerPoint is Impress. It is cosmeticly different from PowerPoint but it has all of its features for making and playing slideshows. It outputs the finished show as a PPT file for playing on a regular PowerPoint host. Office, with PowerPoint, is almost never included with the computer as purchased. It is a commercial product that you buy at a nasty high price. Newer computers may include a PowerPoint player that ONLY plays existing PPT files, those you download or borrow. They can NOT create new ones. If you do career-related work at home or field your company may issue MS Office to facilitate that work. Install it on your home computer, under agreement with your boss, for the occasions you do company work there. Colleges may offer MS Office in a slim version on CD with a student discount. The school's edition may include templates and forms for your work. Some of them may be handy for making slideshows.
A real kludge ----------- In the absolute absence of PowerPoint, Impress, other slideshow application, you can give a show with WordPad. This is part of Windows as a basic word processor that allows pictures to be included in your documents. The effect during projection is untidy, but it does work. Your slideshow is a document consisting of your pictures laid into it in the presentation sequence. You manipulate them with the word processing features, like cut & paste, scaling, rotating, and so on. The trick is to scale the pictures to be EXACTLY one field high. When you do 'PgDn' WOrdPad indexes to the next picture with no overlap beyond the screen borders. You have all of the program's Windows dressing on the projection screen, which absorbs some of the screen's real estate. In a pinch, this method of slideshow honestly does the job. The one crucial factor is that you must build the slideshow on a computer that you bring to the host. It is VERY risky to bring the slideshow file to play on the host's computer. Oh, it WILL play, but the screen resolution, fonts, margins, Windows gadgets, other display parameters will surely differ from yours and corrupt your show. All in all, you BETTER get hold of PowerPoint, Impress, other program that makes and plays PPT files.
Digital pictures -------------- By the 1990s computers could collect pictures from the first digital cameras as computer files. In the early years, cameras tended to use proprietary formats for their pictures, requiring the use of their special software. Pictures could not be exchanged among computers without this software.. This situation quickly vanished when the JPEG standard was adopted. Today all digital cameras output their images in JPEG (or JPG) form. Picture handling software accept JPG files for easy moving around thru electronic means. The opening of the Internet in 1993 for public use broke all barriers to exchanging digital images. They were attached to email and posted in websites. My colleagues simply make a file copy of the picture I request and send it to me by email. Or they give me the link to the picture in their website. Cameras improved, too, from the clumsy bulky expensive units of the 1990s to truly tiny and cheap models today. It is now usual for people to carry a digital camera with them all the time, a practice only occasionally done for a film camera for its weight and size. Now in the 20-thous there is the convergence of mobile computer and telephone that includes picture-taking features.
Camera pictures --------------- Considering now the real digital or 'silicon film' pictures, there are many sources. First is the camera image. This is a picture you shoot thru your camera. 'Camera' is very broad, and becoming broader every year. It's any device that 'takes a picture' like a camera. The device is small and light enough to carry to the target and capture its image. A camera can be en embedded photography feature of an other electronic device. It may be a picture of real scenes. It can be a picture of television screens, books and magazines, signs, other pictures, tabletop mockups, It can be posed like a group photo or award ceremony. The image is captured in the usual picture-taking mode thru your camera. Be SURE your camera is saving the picture in JPEG or JPG form. While this is not the very best way to save a digital image, because it throws out detail during its saving process, it is the universal format for just about all computer handling. Look thru the camera's menus and verify that you ARE capturing JPEG/JPG images. You could be in for a real irritating surprise later if the pictures are in some cockamamie format that no computer program can decipher.
Scanned pictures --------------- These are pictures scanned of a target. 'Scanner' is here a general term for a picture capturing device to which the target is brought. It then is placed on or in the device to capture the image. It can be a regular scanner, acting much like a photocopier with a glass window, lid, crawling light. You can scan just about anything more or less thin and flat. It may be pages from books and magazines, postcards, print photographs, small flat artifacts like medals and coins. Other scanners can be a holograph, X-ray machine, sonograph, laser, to name only a few. The target has to come to the machine and be placed in or on it to get its image. Be sure to capture the picture as a JPEG/JPG file, not something else. If this is not among the choices in the scanning process, surely BMP is. That's the one to go with.
Borrowed pictures ---------------- These are pictures already in computer form that you extract from their source. Taking a picture from a digital source is quick and simple. If the picture comes on a CD, DVD, or other digital medium, copy it to your computer. You may do a copy/paste or drag/drop action. If the picture comes from a webpage or email, right-click INSIDE this picture and pick 'save picture as ...' or 'save image as ...'. A file handling panel opens in which you shayshay to your target disc and enter a filename.
Captured pictures --------------- In some cases the picture displayed on screen is embedded in the webpage in a way that prevents separating it out for saving. In other cases, you may produce a display from a computer program and want to keep the display as is from the screen. Grab the scene by pecking 'PrtScr'. This captures the entire computer screen into the Windows clipboard. To realize the image, open your picture editor, and do 'Edit/paste'. The screen comes up within the document panel of the editor. Many astronomy programs have a 'save' option in its menus. The program instructions explain what this really means. In some cases it means to save the configuration settings as a default for future runs. Nothing is saved from the screen into a picture file. In some cases only the steps that produced the picture are saved. Play them back later to recreate that scene. You have to study the instructions and play with the program to understand what's going on. Other programs do have a real capture function for the screen display with all its colors and detail. In the absence of a proper screen capture within the program, peck 'PrtScr' and realize the image in your picture editor. I make extensive use of 'PrtScr'. It is a powerful means of building slides that are, uh, fabulous, so say my audiences. One point to mind is that when you run a DOS program under Windows, the 'PrtScr' does not work properly. It may be turned off or it may try to, well, print the screen on an attached printer. With no printer or one shut off, you can hang up the computer and force a three-fingered salute. Remember that 'PrtScr' can hold only ONE image at a time. You MUST move it to the picture editor and save it, before cutting the next image. There are applications that allow capture of many pictures into a buffer. You retrieve the pictures later in any order you want.
Saving and naming --------------- To save a picture with the programs own saving function, do 'save as ...' and NOT 'save'. 'Save' keeps what ever name the picture had before, which you may not know or you forgot. You may have a hassle finding the file later without knowing its name. Worse, 'Save' will without any warning overwrite a existing file of the same name. You could without knowing it destroy a good file, now forever gone. 'Save as' presents a file handling panel in which you see the proposed file name and lets you key in your own filename. Name the picture in some manner to later easily find it. In general, do NOT save it under the proposed name and directory. The original pictures will have pretty flaky names. When saved that way they are scattered all over your computer and are tough to collect later. Purposely enter your own name. I name my pictures after the show and a sequence number, like 'alcon01', 'alcon02', 'alcon03', and so on. The sequence is that of acquiring the pictures. You'll shuffle the images into a presentation sequence later. Use TWO digits for the number because you WILL collect in your preparations of a show more than ten pictures. Two digits allows up to 100 pictures as your fount for the show. If you happen to run over that, as I did for AlCon's Coney Island show, continue with hex notation: 'A0, A1, ..., A9, B0, B1, ...'. That's a LOT of pictures to choose from for a thirty-slide presentation! Pictures you come onto will prevalently be in JPH form, but BMP and GIf are common. All three can be used as is in the slideshow program. Be careful to leave the filetype alone when saving. It's in a separate input box near the one for the filenmae. As long as it's one of the three JPG, GIF, BMP, you're set. Renaming the pictures makes them all gather together in one zone in the file listing of your target disc. You may make a new directory with a germane name to save the pictures into. My pictures for the 2009 Astronomical League convention were held in directory 'alcon09'.
Pixels ---- Chemofilm has a thin layer of chemical made of microscopic grains. The blending of these grains to the bare sight makes up the complete picture. The grains are randomly dispersed in the film and are impossible to reference or modify individually. A digital picture also has microscopic grains, called picture elements or pixels. They are arrayed in a grid like tiles. They, unlike film grains, can be addressed individually for manipulation by the picture editor. Each pixel has an X-Y coordinate, like on a graph, by which the editor knows which is which. When light impinges on a pixel in creating the picture, the pixel acquires a value or count. This corresponds to the transparency or density of a grain in chemofilm. Most digital pictures work with a range of value from 0 to 255. O is darkest; 255, lightest Actually each pixel has FOUR values, one for white, red, green, and blue. The mix of these values makes the pixel show the correct color and luminance in the scene. Besides showing the image on screen, the picture editor can display the values for any pixel by setting the cursor on it or keying in its coordinate. This information is very useful when manipulating the image and is a faculty entirely wanting in film pictures. Because of the grid arrangement of the pixels, a picture is often dimension by the number of X and Y pixels, like '640 x 480'. This menas there are 640 pixels on the X-axis and 480 on the Y-axis.
Image manipulation ---------------- Unlike chemophotography, it is easy to manipulate a digital picture. You need an image or picture editor. Paint comes with Windows but you may want something more full-featured. Photoshop or Photoshop Elements are the top dogs in picture editing. There are many other good editors. I personally use Paint Shop Pro, a commercial program with lots of features, all simple to get at and use. GIMP is a new other favorite one and it's free for download. Being more complex, it is harder to learn. You are free to modify your pictures to suit your presentation. When modifying a borrowed picture, note that it is adapted from its original source'. Examples of manipulation are: ----------------------------- * altering overall brightness * altering overall contrast * altering color balance * negating colors * altering highlights * erasing sections * removing blemishes * erasing sections * adding text * combining pictures * converting picture formats ---------------------------- Before working on your slideshow pictures familiarize yourself with the picture editor's features and operations. Experiment with scrap picture. Give yourself plenty of exercise with the program. One evening isn't enough for a program newly unpacked.. Look for and learn to use the 'Undo' feature! This undoes the last operation and restores the picture to its previous state. Many editors can undo only the very last operation, so you MUST pay attention to your work to avoid horrible irrecoverable mistakes. It is well at the start to work on a COPY of the original picture. If things go too wrong, junk the picture and cut a fresh copy. Make intermediate saves. That way you don't have to reconstruct all the previous steps if you have to junk the picture. Pull back the last saved one and continue from it.
Altering overall brightness ------------------------- The original picture, such as one taken at night with your camera, may be too dark. The picture editor has tools to lighten (or darken) the image. All parts are changed by adding a certain count of brightness steps to each pixel in the scene. There's a limit to how bright or dark to make the picture. When the pixels start to saturate, reach their upper or lower limit of count they stop brightening or darkening. Further effort to apply light/dark distorts the brightness regime of the picture. A few editors may add this count in a proportional manner to prevent saturating pixels already at a high count. Reverse thinking for darkening a picture to prevent saturating near value 0.. Too much brightening can also veil details in the brighter areas. Too much darkening conceals details in the shaded areas. In general apply bright/dark to highlight the important parts of the picture.
Altering overall contrast ----------------------- An editor has many ways to change contrast, some with strange names and concepts. Here I explain the usual sense of contrast, what happens when you turn the contrast knob on your [old] picture-tube television or computer monitor. The scene details are muted or exaggerated and shadings are accentuated. Extreme high contrast makes the scene black or white all over. Too low contrast gives an overall gray cast. Some where in between you may capture all the texture in the scene with a pleasing range of dark and light shades.
Altering color balance -------------------- For graphical images, illustrations, cartoons, graphs and plots, charts, you better leave the colors alone. For photographs the color rendition can be badly skewed by the ambient lighting to yield an ugly picture. You can to some extent correct this imbalance of color by applying more or less of the three primary colors to the image. Programs differ on the means of doing this. They in general tell you what portion of red, green, and blue is in the picture and you change this mix. The program may use the subtractive colors of cyan, yellow, and magenta, but the concept is the same. As a first cut, note the color that's in excess, like red for a picture taken under incandescent lighting. Reduce the portion of red (or increase that of cyan) and assess the result. Here's a guide to the relation of the primary colors to help select the ones to play with.
red / \ (minus green) magenta yellow (minus blue) | | blue green \ / cyan (minus red)
Each color is the blend of its two adjacents and is the negative of its opposite. To increase one, you may decrease its opposite or increase its adjacents. A more complete chart includes a radial component for brightness, from black in the center to white around the edges. Just how much fiddling with colors you do is pura mente a matter of personal taste. It also depends on your acuity of color perception, which tends to weaken with age. If you're squeamish about messing around with the colors in your picture, it's better to leave them alone. Have the 'Undo' button handy.
Negating colors ------------- This a very welcome feature of my slideshows. Time and again I and others are annoyed by the blast of white space on the projection screen in a darkened room. The picture a white page with black or colored lettering, like charts, diagrams, graphs, text. Many of us find it hard to read the lettering against such a harsh background. A scene with dark background and light lettering is vastly easier to read and is orders more comfortable to view in the dark. For graphics, charts, plots, other line work, I routinely negate the colors before saving the picture. The dark lines and letters are now white (or light color) and the field is black (or dark color). For such pictures the exact colors often don't matter. They were arbitrarily chosen for the original with no peculiar meaning. There may be a caption that refers to the original colors. 'the red curve is ...'. You have to remove this caption with the erase feature, explained later. I use negative colors for starcharts, too, if the original has black stars on white field. Apart from the ease and comfort factor, the scene looks more real compared to the sky. The picture editor has a feature for 'negative' ,'inverse', 'reverse', 'complementary' colors. It takes the count of each pixel in the four colors and subtracts it from the maximum value of 255. A pixel with count 25, a darkish one, becomes one of 230, a bright one. A pixel of count 240, a bright one, becomes one of value 16, dark.
Altering highlights ----------------- This is a tricky subject but it's like applying contrast to just the bright, dark, or intermediate areas. This is usually done by specifying the ratio of each segment in turn. There seems to be no common method across programs for what the numbers mean. You got a lot of playing around to do. The idea is to judge that certain parts of the picture are good while others need enhancing. You then apply highlight to those parts as part of a high, middle or low lighted zone. The trick is that if you enhance one feature in the scene, you also enhance other features within the same lighting category, how ever the program defines that. It may not matter or it can upset previous alterations you did. A curious feature of highlight is that some program do not act in a linear manner with the numbers. If you alter one zone, its new base value may also be changed, so you can not obviously backtrack to the previous state by adjusting the numbers manually. You better know how to pull the 'Undo' cord.
Extracting sections ----------------- This takes a delineated section of one picture and keeps just it as a new picture. Do this when there is a particular part of the picture you need in your show without distractions from unwanted parts. One major application is to trim a screen-capture image. The picture has the Windows dressing around the edges and all you really want is the scene inside one of the panels. This is a two-step process. First delineate the desired section with the 'Box' feature. This turns the cursor into a rubber band that when dragged over the picture ropes in a rectangular section. The usual instruction is to start at the upper left or lower right corner of the desired section and sweep to the opposite corner. When the mouse is released a marquee, a line with chaser lights running around like on a theater sign, is left behind. If you continue the extraction procedure, the area inside this marquee will be captured into a new image. You have the chance to back out, like with a right click or the 'Escape/cancel' button, and try again. When satisfied you got the correct selection, invoke the capture. Do study the program's instructions. The selection will appear in a new picture panel, ready for you to continue working on it. It's wise to first save this picture in case you goof up and need to start again. You fetch a copy of this new picture and not go thru the extraction steps all over again. Save within the naming system of your other pictures. Your program may have other selection shapes, like a circle or a lasso. These I find poor methods for making slides, which must be rectangular in shape. On the other hand, a circle could be useful to extract a section that is then pasted into a 2nd picture. See the section on combining picture later.
Erasing sections -------------- Erasing in digital image manipulation really means overwriting a section, like painting over a wall. The trick is to choose a color that blends with the surrounding area so the work does NOT look like you painted over a wall. This method is for small extraneous bits of an image that can distract your audience, like a lamp in a shaded area that doesn't mean anything for the slideshow. You want to erase the lamp and leave a uniform dark area. You may for a graphic want to erase the labels or caption to later add in your own. You may have to erase parts of the whole picture that protrude into a new selection you extracted. The editor has some way to pick up the color of a point in the scene and show that it's picked in a color patch some where in the margin of the screen. Look carefully at the area you want to erase. If the color around it looks smooth and uniform, your work is simplified. use the pickoff feature to grab the color of a point next to but outside of the erasing area. Then with the eraser, airbrush, mop, spraycan tool, go and 'paint' over the erasing area with this color! Be very gentle at the edges of the erasing area so the tool strokes don't show. Use short bursts from the spraycan, for instance. If the color graduates around the erasing area, you must do the erase process in several stages. First erase around the point where you picked off the color. When you move to a part where there is a shift in color, stop. Pick off a new color from near this next spot and continue. The spraycan can help blend the erased portions to make a smooth transition around the erasing area.
Removing blemishes ---------------- This is a finer version of erasing sections. There may be a couple pixels out of order in the picture that should be removed. They could, for example, be dirt on the paper you scanned or on the window you had to shoot thru with your camera. First pick up the color next to, but not within, the rogue pixels. Then use a pencil or pen tool to 'dab' or 'peck' at the pixel. It will turn into the new color and blend into its surrounds.
Adding text --------- Among the best manipulations of a picture is adding titles and labels and captions. You may want to name parts of the scene and attach a date or location note. You may want to point to certain parts and mark certain points. All of this is done thru the editor's 'text' and 'draw' features. Choose a simple open typestyle. Fancy, thin, condensed styles are tough to read from a distance. My own runaway favorite is 'Comic sans serif' that resembles handwritten block lettering and is extra clear and legible. I myself stay with horizontal text, not trying aligned or rotated text. This leaves the audience upright in its seat. The thing to mind is the color of the text on the background it sits on. Some programs will automaticly make the text a contrasting color, like the negative of the base color, while others use a fixed color that you choose. I and others are routinely frustrated by text, on webpages and slideshows, that plain disappears over some parts of the background. A compromise method is to use 'shadowed' or '3D' text. This is text written with a shadow behind each letter or a raised shape with shadowed sides. This text is legible over just about all backgrounds, from light to dark. I uss it for labeling photos of the Moon, where the text can fall on maria and terra alike. For text on a uniform background, like the sky in a starchart, I use flat text of a light color. You have the chance to see your text in the scene before dropping it into place. Each program has a 'hot spot' where the text will sit when let go in the picture. Study the instructions. Pay attention to the size of the text! It has to be legible from th audience seat several meters from the projection screen. It can not be tiny lettering you can read with your nose against the computer screen. it also can not so large it overwhelms the scene like a billboard. Size the text by importance and possible obstruction of other features of the scene. I use a large size for a title and a smaller one for labels within the scene. You probably noticed how on my starcharts the labels don't interfere with each other and hardly ever cover important stars? That's because I do NOT let the planetarium program insert its own labels. Most are ineptly placed and sized. I manually label each and every star, cluster, planet in my charts. I label only the items I need, leaving every thing else blank. i place the labels so they don't interfere or obscure other parts of the chart. If the label is too long for a single row of text, enter it piece by piece on separate rows. You do have to gauge the row spacing and centering. Use leaders to attach a label to its target. This may be a couple dashes, hyphens, like I do for my starcharts. The front and back slashes are also good leaders. In some cases it's best to draw a short line with the 'line' tool from the target to an empty area and then attach the label to it.
Combining pictures ---------------- This can be useful when you want to have a small inset within a larger picture, like a detail of a starfield to one side of a constellation picture. The exact process is unique for each picture editor, so studying the instructions and experimenting is a need. Open both the main and inset pictures. Note the shape and proportion of the inset picture. Do 'copy' on the inset. Select in the main picture an area, usually in one corner, of the desired size and of the same proportion as the inset. This is done with the 'Box' feature to enclose the desired area. Now do 'paste'. The program may ask if you want to paste into the selected area. The inset is bunged into the main picture within the selected area. An inset may also be round, if it was extracted with the 'circle' function. The target area to paste this inset into has also to be round. You may with the 'line' and 'text' features point to the region in the main picture covered by the inset with a suitable label. It may be good to outline the inset with a border using a thick line with the 'line' tool. Or do a proper 'border' on the inset before copying it. Save the picture under a new name, because you may want the unaltered main picture for some other purpose later. Usually only one picture fits well onto an other. Trying to make a collage can be messy. The standard application is the inset detail for a region in the main picture.
Converting picture formats ------------------------ It may be necessary to convert a rogue picture format into one that PowerPoint can accept, notably JPG, GIF, and BMP. The easiest way to do this is to open the picture in the picture editor and then save it into a file of the other format. This assumes you have an editor that accepts many different formats. Some take in only a few kinds of picture, leaving you with no way to work with the rogue one. With the picture open on screen, do 'File/save as'. In the file handling panel that opens, you must change not only the filename to your numbering scheme, but also the filetype. This is in a picklist near the filename. Select JPEG or JPG.
Assembling the show ----------------- Having acquired, manipulated, saved all the pictures you may need for your show, you must now arrange them in the presentation order. One way is to print the pictures one by one and then write on each its filename. This last step is vital because many programs print pictures without their filename. With no name right on the picture you will never be sure which picture you're holding in your hand during the sorting process. To save paper you may print two or four pictures per sheet. More than four pictures are too small to see well what they are. Label and cut out the pictures. With the pictures properly labeled, shuffle them into order. The order WILL NOT be the same as the acquisition sequence. When you actually build the show you must pull up the pictures in the PRESENTATION order by calling for them by their ACQUISITION number. Got that straight? Recite the show while looking at each picture. Is this picture really needed? Is its features already part of an other picture? Is there something missing that needs a new picture? Is the text clearly legible at arm's length (to simulate a back-row seat)? Try not to duplicate scenes. One or two of a given scene is plenty. Each picture should have its own internal value to support the show, not just to give more examples of the same point. Just do NOT throw up pictures for the hell of it. Maintain a flow of thought or theme so the pictures link together. Think of the awful slideshws you saw before. Why were they so terrible? Then avoid those features in your show. In this winnowing process you'll set aside many of the pictures you gathered. You may even set aside some you manipulated in the picture editor. Keep these for possible future shows or to customize a show for other audiences. Leave them in the show's directory.
Fire up PowerPoint ---------------- I use PowerPoint, as does virtually every one else. First thing I do is choose a background for my slides. I find that a plain one-color field is best. I do not use a wallpaper background or one with a design on it. After picking a soothing color, I tell PP (short for MS PowerPoint) to keep this background for all the slides in this show. I make my first slide by doing 'Insert/new slide/insert (again)/ picture/from file'. I shayshay to the show directory where I stored my pictures and scroll to the first one in the presentation order. This is the first one in my stack of printouts. from the hand written label on that picture I know which of the files to call up. Let's say this is alcon07.jpg. It's the 7th picture I acquired but the first in the show. Alcon07.jpg is bunged into the background on the slide panel. To the left of this panel is a list showing slide #1 in progress. As each new slide is built it's added to this list. You can view any slide by clicking it on this list. In general the picture will be way off sized to fill the whole panel. It has handles around it by which to pull and drag it into the largest size that fits within the panel. I like to fill the panel and leave a thin border of background around the slide. Gauge the margins top/bottom, left/right. The top and bottom may be unequal but the left and right should be the same. When satisfied with the arrangement, I move the cursor off of the panel and do 'Insert/new slide/insert/picture/from file' for slide #2. I repeat the fetching, sizing, aligning process all over again for slide #2. This slide is also placed into the list on the left. I work thru all of the slides to complete the show. Along the way I save the show, in case of computer or power glitch, under the name of the presentation, like 'alcon.ppt'. If I have to give the show to the host to play thru his computer I name it 'pazmino.ppt'. That makes it easy for the host to fetch when it's my turn to speak. Having done all of the slides and packaged the show, I switch to 'View/slide show' and try it out. I usually find that a slide is out of place or I forget to put one in. I switch to 'View/slide sorter'. This lays out the slides like the chemo ones on a backlighted table. By drag and drop I rearrange the slides into proper order. Where a slide is missing I note between which two it belongs. In the 'View/Normal' mode, where the slide show is compiled, I scroll to the place to insert the missing slide and do 'Insert/...'. The new slide is inserted between the others.
Extra functions ------------- PowerPoint has a wide selection of slide transition. This is the way one slide changes to the next. I so far haven't used anything fancy. I stay with the click! of the old slide projector. The transitions can add interest but please don't make a show just for that. PowerPoint allows adding video and audio to the slideshow. These are treated like any other slide, except that its content is sound or movie. I haven't needed this facility yet. You can also make evolving slides where its text comes up bit by bit with each advance to the next slide. This is done by making the slide with the first bit of text. Pick THIS SLIDE as the next new slide and add the next bit of text. Repeat until all the text is displayed. You really have several slides but they are in register except for the new lettering on each successive one. It looks like the one slide magicly adds text as you speak.
Modifying existing shows ---------------------- Occasionally you'll find a PPT file ready to show as is. If the show is a good one, you may show it to your audience, just like you show paper albums, posters, films which obviously you didn't make yourself. The title or closing slide usually gives the attribution. However, as in my case for both epsilon Aurigae and LCROSS shows at the NYSkies Seminars in summer 2009, the original slideshow was too shallow for our astronomers. I modified them by adding slides from other sources and omitting some of the original ones. I noted in the title slide that this show is adapted for NYSkies. Open the existing PPT file and then work with it just like for a new one. If you do this, be SURE to add text to the attribution slide that this peculiar show is adapted for your talk. This is essential if your show is preserved in the meeting procedings.
Testing the show -------------- It may take a couple iterations to get the show into final form. One crucial thing to mind well is that the show has to fit within the time slot for your talk. If this is 20 minutes, you have to show and narrate your slides within 20 minutes and no longer. Have a clock in front of you to mind the time. A sports watch is good because you can zero it at the start of your talk. Recite the chow, aloud if you must, at a slow and steady pace. Don't rush. Don't mumble. Say each word clearly and audibly. As you flip to each slide state what is shows and point out its features. You save lots of time by leaving out noise words like 'Here is a slide of ...', 'The next picture is of ...', 'I took this picture to show ...' . Just state the substance of the picture and you'll be amazed how easy it is to keep within your time allotment. If you interrupt the show and have to resume, start the slideshow again. Right-click in the first slide. On the popup menu pick 'go' or 'go to slide' and then scroll to the slide where you left off. This resumes the show from that point. You do not have to go thru the show all over again from the beginning. Save the final show on your computer and on the medium needed for the presentation. This is typicly a storage card, stick, CD. Label the medium with your name and meeting so the host returns the right one. That's all there is to it!
Working the computer ------------------ I offer assorted tips and hints for giving your slideshow at the presentation session. Here are several relating to the computer. In the next section are some for the delivery process. If you have your own laptop with the show loaded on it, you must know how to work it in the dark. Laptop keys can be hard to read in the dark. Place bits of masking tape on the critical keys. Mark the alt/F4 keys to close PowerPoint and then your computer after your talk. The light colored tape stands out in the dark and its texture gives tactile clues to press the right keys. Have with you the video cable to attach your laptop to the host's projector. The host should have this, but it can go missing or, yes, the previous speaker took it away by mistake. You also need the power brick, specific for your laptop, to prevent low-battery problems during your show. You will also need it for using the machine else when nd where during the meeting. Know how to turn on the video socket for an external display. Some computers always echo the screen to the video output socket. Others require some queer key combo to turn on the socket. The host's projector NEEDS the signal from your computer to project your show. Because you may not have used this feature before, you have to study the computer manual. If possible sit down next to your computer to minimize blocking the projection screen from the audience. If you have to stand or there's an obvious zone of blockage, advise the audience about it. Offer that it can shift seat for a clear view. You may attach a remote control for the computer, using an infrared connection. Be sure this works by actual test and keep a clear sightline from the wand to the sensor on the computer. This is one way to let you walk around by the projection screen and still operate the laptop by yourself. Do NOT count on a wireless Internet connection during your talk. In all places I went to, the signal strength wavered all day with frequent dropouts, languid speed, and dead spots. To show what a webpage looks like, make a slide of it from a PrtScr capture. The image is a static one, but that's better than getting tripped by a lazy signal or slow service during your talk.
Giving the show ------------- Inspect the floor for wires, then avoid that area to the max during your talk. Stepping on wires can unplug equipment, sometimes not noticed until they are next needed. Tripping on wires can injure you in a fall. The host should try to gather the wires into a side space, cover them with hunks of rug, or station an agent to deflect people away. Put any glass of water, a common courtesy for speakers, away from the computer and projector. You do not want to spill water on them. One trick is to take a drink before the meeting and leave the rest for after the talk. If you prefer standing by the projection screen, away from your computer, ask the host for an agent to run the computer. The taped keys will make his life a whole lot easier when faced with an unfamiliar keyboard. When speaking, look at the audience, not the computer. Speak slowly and carefully because the audience in the dark no longer has visual clues to your words. Where spelling is important, say the letters with the phonetic alphabet. The universal standard is the NATO system, but the ham radio system is still common in the US. You may use any unique distinct words that clue the audience to the initial letter. Make sure the words are indeed unmistakable. do NOT fiddle with paper notes! You will mix up the sheets, drop them. They rattle and crinkle in the microphone.You look down at them, not at the audience, they may be hard to read in the dark. By testing your show before your talk, you know the sequence and content of your slides. The image itself is the clue to your narration.
Insurance ------- Electronics are wonderfully, when they in fact work. It can happen that your computer, the host's machine, the projector, cables, power cords, fail. You slideshow is killed, along with perhaps many others. There is an insurance policy you can take out. After you arrange your pictures in the order for the show, get a printout of them on viewgraph sheets. These are clear plastic sheets that go thru the printer like paper and take up the picture as a see-thru image. The sheets MUST be compatible with your printer to prevent kaboshing it with melted or shredded plastic. Read the package label carefully before buying the sheets. Stack the sheets in the show order, with blank paper sheets in between. You may use the preliminary printouts of the slides so you picture on paper clues you to the next image in your show. Put the stack in an envelope or folder with strong bands to prevent a disastrous spill. Ask the host to have at ready a viewgraph project, also called an overhead projector. If the electronic gear konks out, have the overhead machine rolled out for you. You give the slideshow by placing the see-thru pictures on the window, like a photocopier, right side up and top toward the back of the window. An arrangement of lamps, mirrors, lenses projects the picture onto the screen. The set of pictures, in presentation order, sits on one side and the spent pictures go in a pile on the other. Your narration has to louder and clearer to hear above the fan noise in the projector. You must also stand to one side to avoid blocking the beam from the projector. The viewgraphs will be of lower quality than the digital slides and may be only in gray-scale, depending on the printer. In a contingency they'll save your show from being called off.
Laser pointers ------------ Please use a GREEN pointer. A red one often is too weak. Its dot gets lost in a busy scene. It is further more surprising how many people's eyesight is only weakly responsive to red! To them red is perceived as a dim dark tint. Laser pointers come in several colors, but so far red and green are far and away the most easily available, Go for the green, even if it costs a little more. Be EXTREMELY CAREFUL with your pointer! NEVER aim the beam at or near other people or into a space occupied by people. NEVER sweep the beam into the audience by accidently holding the trigger between slides. LET GO OF THE TRIGGER instantly the laser is taken off of the projection screen. This is a real problem in meeting halls with mirrors or other shiny surfaces and fixtures. NEVER horseplay with a laser to play tag or sci-fi warrior. NEVER attract a person's attention by 'dotting' him. NEVER leave your pointer loose where innocent people can play with it, specially children. When not in use, keep the pointer out of reach. NEVER experiment with the pointer from your hotel room or open field to determine its range. From safely-conducted tests, the ordinary green laser pointer sends back a visible reflection off of stone or brick out to about TEN KILOMETERS away. The beam is still easily noticed after a twenty kilometer round trip and absorption by a dull wall. Now that you know, there's no need to experiment. Let only competent persons borrow your pointer and then only under your immediate supervision. You really don't want liability by reckless application of your pointer behind your back. A good strategy is to treat the laser pointer like a firearm and apply its safety principles. In fact, an ordinary commercial green laser pointer IS a weapon that is used in crimes. Apart from the headlines of firing at aircraft, the pointers are used to dazzle or distract sports players, vehicle drivers, farm and zoo animals, kids and gang members, neighbors, and police in chase. Being caught misusing a laser pointer can earn you deep time, fines, civil penalties, and professional and public disgrace.
Conclusion -------- Presenting slideshows was always a part of an astronomer's skills. From chemophotography the method is by the 20-thous just about completely shifted to digital imaging. Apart from the form of the prime images now being on silicon rather than film, there are now many more ways to obtain the prime images. Once having these pictures, you may manipulate them in useful ways with ordinary picture editors. They allow for extensive customization of the pictures to accommodate your audience. Assembling the slideshow is done on computer with PowerPoint or a workalike, taking about as much time as it did to assemble a film- based slideshow. Once compiled, the show is saved to digital medium to bring to the presentation host.