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Photographing Miniatures

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AModelMan	Photographing Miniatures	Lead	[-]
Posts: 257 (10/02/07 22:59:33) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	Tags : None Initially I thought this would be a couple topics and that would be that. I started duplicating this thread over at Clavius Shipyards last week and things spiraled out of control. I'm covering it all from lighting, lenses, filters, greenscreening and tracking. Everything I know and the kitchen sink too. After a huge burst last week, I've got 20+ distinct topics in ahalf dozen threads under one board over there now. There is much more to come. So I'll leave some of these posts here. If you want the bulk of it, pop on over to Clavius. It's in an open board, so you don't even have to register to read any of it. http://cmk15.proboards92.com/index.cgi?board=photography Last Edited By: AModelMan 06/23/08 20:02:38. Edited 2 times.
AModelMan	Gray Cards and Calibration	#1	[-]
Posts: 228 (05/31/08 22:15:47) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	This is not a definitive treatment of this vast subject. Chances are that we all know a little and can together create a great thread out of this -maybe Photography could have its own forum! Please help me out with suggestions and critiques ------------------ There has been a lot of chatter in the D-7 forum about color casts and how a gray looks violet to some people. There are lots of reasons for this, from initial lighting conditions of the subject -both direct and ambient light, paint mixtures on the model, camera settings, scanners, printers, monitors, alignment with stars, how many chickens you sacrificed the previous night and much, much more... "So..." You're now thinking. "With all these variables, how can anyone be sure of what they are really looking at in the first place? What is reality anyway?" It's all about *calibration. Calibrate one thing you are unsure of to something you are sure of and proceed from there. And to start at the beginning, subject-to-camera calibration is key... "Well, my camera is self-calibrated! It does the white balance and* exposure all by itself, it's fine the way it is." Well, no... It's not. The generic camera is generically detecting generic qualities and generically adjusting generic settings based generically on what it generically thinks it is generically seeing, based on who generically made it, when they generically made it and with what generic components! You see where I'm going with this? "Oh jeez!" Every camera in the world, even within the same make and model group, (digital and analog) is going to see things differently. "Cripes!" Don't give up! There is a simple and ingenius solution!!! It's called a Gray Card. And, no... You can't simply print one off your printer, nor paint one, nor rig a homegrown one either... Sorry... A proper gray card is not only exactly 18% true gray, it reflects a certain percentage of light back to the camera, typically 1%. Most gray cards are also, conveniently, true white on the back. You can get one at any photography store (Ask for it by name!) for $10-$50 depending. The basic idea is that you place the white side in front of your subject and get your proper White Balance. Lock it off! Note that there should be no hint of any other color in the camera viewer whatsoever! Then, flip the card over. The gray side will give you your ideal Exposure V alue -the darks won't lighten, the lights won't darken. Let the camera set the value. Then switch to manual (if you can) and Lock it off! The gray card above also has a target for focusing -let it focus and Lock it off! (assuming the distance from camera to subject will not change -if it does, so will your exposure!!!) Take a photo of your gray card first!!! Then proceed with your photo session. When you upload the pictures (scanning is another topic I will get to), you will have your true gray reference. You will know it is true gray because the card is true gray. If the image appears even slightly tinted on your monitor, you now know that it is your monitor that is out of whack -now we're getting someplace! --------------------- While there are expensive soft and hardware calibrators, here's the free, easy way... Many monitors have the ability to change the RGB values with push buttons on the front of the monitor somewhere. Have a look around and then dig through the menus until you find the on-screen controls. Some flat panels nowadays think they're perfect and don't include this feature -you are out of luck at this stage, skip down, but read on... First, close your curtains and get the brightness in your room to the goldilocks value -not too dark, not too bright (unless your room is always one or the other, in which case, keep it that way!). Second. Set your desktop color to a custom mid-gray, ideally 128,128,128 for red, green and blue. Third. Hold or place the gray card next to your monitor. See the difference already? Finally. Go into your monitor controls and change the RGB values until your desktop gray is as close as possible to the gray card gray. You will not likely be able to get a perfect match, just go for very close... While you're at it, set your contrast and brightness to 100% . Now drop your brightness until you get close to the value of the gray card, not exactly is ok. An additional step...Your graphics card should have some form of calibration feature as well. Dig around and use it! This will finesse your settings! Congrats! Your monitor is now calibrated!!! --------------------- "Great! Now how about my printer?" Easy. you are going to create a custom image in your paint program, photoshop is common so I will use that as an example. Typically a new image is created in rgb color space (don't worry, just know it's rgb). 'But Tom, my printer uses CMYK colors, not RGB. What's up with that?' Light is pure, pigment is not. Monitors use light, printers use pigment. Add every photon color you see and you get pure white light, remove all light and you get black. Add every pigment color and you get muck (black if you keep going), subtract every pigment color and you get white! Printers can't produce RGB because RGB is light,and printers are pigment. So they use CMYK, which approximates RGB in many cases (some new printers also have Green and Orange color tanks -be psyched you are getting huge color space (gamut))! Create a new file. you will see 'color mode' option, select CMYK. Or create it any old way and goto Image>Mode>cmyk You are going to make 4 simple stripes on this sheet, you can use a big brush or the marquee, you can make it sloppy or precise. Goto your color swatch and move the slider so you get pure Cyan, paint one area, get pure Magenta, paint another area, pure Yellow, then pure black. Print this file. Once dry, hold it next to your monitor. Big difference? Go into your printer controls and change the defaults by a few % points for each color. Print again, adjust again. To complete the loop, scan the the final print back into photoshop. It should be close. If not, then you have to adjust your scanner's defaults in a similar way. --------------------- You can calibrate your monitor to your printer, or your scanner to printer to monitor or any combination thereof!!! It's individual preference. Personally, I say go the route I described. Basically, calibrate all your devices to what you consider to be the most important device. You could afterall, start by scanning your gray card and calling your scanner the most important, calibrating everything else to it! Not eveyrbody has a digital camera these days. If you primarily scan your images in, your scanner is most important and you should rework the steps I gave you here to reflect this! Simple, huh? "> Magenta color casts are the most common in monitors for some reason, though occasionally, you will see yellow casts as well! You are now ready to say, 'Screw all that! Close enough is close enough! If I see violet in my D-7, I see violet! Darn it!' Happy shooting! -tom Next topic: Lighting your miniatures for photography! Best Regards, -t
AModelMan	Greenscreening on the cheap	#2	[-]
Posts: 229 (05/31/08 22:29:47) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	I suppose before I get to lighting, I should concentrate on all the components of the shoot first. As these are miniatures we are shooting, here's a quick rundown on greeenscreening. The basic notion is that by having one color in the background, you can simply (using the photoshop magic wand for instance) select the color, delete it and replace it with your new background. This is called 'keying' in visual effects, but is most commonly known as green or bluescreening. If not for this trick, you would have to manually isolate your subject and delete the old background. In vfx this is called 'rotoscoping' and has been around for some 90+ years now. Bluescreening has been around for at least 40 years. Back to keying. There are three colors that are best for keying. In order they are: green, blue and the rarely used orange. But you can't use any old tones mind you, they are very specifically chosen for their reflective frequency. One color is used over another depending on the subject being shot. So while you could use a blue screen for someone wearing blue jeans, going green is the better choice in that circumstance. The specific blue and green used are often known as optical blue and optical green. Order the optical stuff online and you are going to pay $50+ per gallon! Yeeesh! A word about color channels. Light is, of course, funky stuff. It's deceptive and plays tricks on our eyes all the time. From infrared to ultraviolet and all the frequencies outside of our visual range. Of these, red has the shortest (tightest) frequency (waveform) and blue has the longest. Leaving green as the moderate in the middle. So, if you dig into the photoshop channels and look at each for any given image, you will note that blue has the most 'noise'. Toggling between the red and blue, you will actually see that the blue image is 'looser' than the red under some circumstances. That is to say, if you have any motion blur in your image, red will have the least blur and blue the most. And again, blue will have the most noise and red the least. As red occurs in all earth tones, it is never used, though the rarely used orange sometimes is when blue and green are not feasible at all. This therefore makes green the best all around choice. While blue is the original color of choice, it has been losing preference to green over the last few years as the digital tools to study these niceties are refined. Given all this, I went looking for a cheap alternative to optical green that would be adequate for non-professional uses.. As it happens, a grocery store chain out here in SoCal sells 18x24" sheets of neon green construction paper for about a dollar a sheet. Nice! Under white light, this stuff reflects almost entirely in the green channel. The less red and blue in the tone, the easier it will be to key. I will put some scans on here at some point to demonstrate what I am talking about. But for the moment, the guy at this thread I came across the other day explains it all quite nicely w/ plenty of visual examples! http://dvinfo.net/conf/showthread.php?t=109612 Wow.! There's a goldmine for you! One thing they don't address in the thread is that dumping paint over a roll of canvas will alter the green tone as the canvas material properties are different.than the paint chips. Cloth versus wood pulp. This is a minor notation though. A quick note on lighting your greenscreen. You want to isolate the lighting on the screen from your subject. The greenscreen must be evenly lit to give as close to a single tone across the entire surface for easy keying. Also, you don't want to use the same lighting on the background as you do on the subject! I'll cover that more under lighting when I get to that. Next up however I think will be cameras, then lenses, filters and so on. Anyone of these aspects that is subpar has to be compensated for with superior technique in the other categories. Bad this requires excellent that... That's it for the moment. There should be enough there to digest for some time. Best Regards, -t Last Edited By: AModelMan 05/31/08 22:50:01. Edited 4 times.
AmodelMan	Green Screen part 2	#3	[-]
Posts: 48 (06/02/08 13:55:32) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	All that is good if your camera is 'locked off', that is to say, there is no camera movement at all. If you want to throw a camera move in, whether live or as stop motion, you will need Tracking Markers on your background (BG). The easy way to do this is to use a contrasting color on the green (such as red) for your marks. Black is not so good as it would tend to disappear and your track would get lost. You also wouldn't want to use a silver marker as it would disappear as the change in light incidence (angle) would change the luminosity of the silver and again your track would get lost. Aluminum foil sounds like a good idea as it is bright, however glints can do messy things with your imagery, so avoid that and stick w/ red. A blue screen would work best with orange and an orange screen would use blue (the opposite colors in the color wheel) Typically a '+' sign is used, however tracking programs (such as After Effects) love triangles even more. You could use dots or any small shape. What you would do is either use a sharpie and mark at regular intervals and draw your shape. Or you could cut your shapes out of construction paper and glue them on. I suppose to do it real heap and fast, you could use the circle debris from a hole puncher and just dab those on. It is important to keep things regular and evenly spaced. If your markers start wandering across the background sheet, you tracking program will also have a tough time tracking them and could even introduce motion that does not exist! More to come. -t
AModelMan	Keying a Screen	#4	[-]
Posts: 233 (06/08/08 22:42:24) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	I will show some regular GS probs in another posting. Here's a sample of what I'm going on about: The basic photo. This shot violates one big rule I gave: Light the screen independent of the model! Were this properly lit, there would be no vignetting around the corners and the rear ground shadow would be gone. The BG would be one nearly perfect tone of green. While this particular shot is acceptable for these purposes, were you doing hundreds of these, doing it right to start with pays off huge down the road. The BG is Neon Green 18"x24"sheet for ~$1 at the local grocery store. This stuff essentially is studio quality! Take the photo above into your PShop and pass the eyedropper over the green, while watching the color values in the Info palette... Nice! Of 256 tonal range, this greenscreen has (w/typical.): Red will be a deep gray: 10-30 (20) Green at near pure white: 220+ (240+) Blue should be near black:.0-10 (1) This stuff is gold! Studio screens costing tens of thousands get these numbers at their best. Below is each 8bit channel of the image. In PShop, the tool you want is the magic wand. (In compositing software there are other methods as thousands of frames can be involved.) By selecting the green, simply delete it now. You can go into Channels and create a specific mask, but nothing to worry about. After deleting the green, you will notice fringe. This cannot be helped. Go to Hue, choose Green and drop it's saturation to 0%. This will give you a gray roll off and negate any reflected color off the wall. If your mask is still active, rt click and feather it to a 3 or so. Hit the delete key several times. If needed, roll the Burn tool over any highlights that look wrong around the edges. I had an old background hanging around so I threw that in there. Next is color correcting the model to the BG. Blur the BG and, as it is cg, add some noise to match the photo. Tweak until it's close to perfect... Or push it over the edge. In this case, I pushed it further into an art piece.with a different BG. Every color on the model was drawn out of the original. I did no painting in the pic whatsoever. It's all in the tweaks. PS Sorry for the non-ASO model. Don't have any handy or finished for that matter. Best Regards, -t Last Edited By: AModelMan 06/09/08 01:11:13. Edited 10 times.
AModelMan	The Stage	#5	[-]
Posts: 234 (06/08/08 23:15:13) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	Here's version one of the setup. As you can see, the room corner and the table top lip are very hard edges. This is a big no-no! Here is version 1.5 of the setup.The corners have been rounded. The mess on the table stayed through the transition. The further away you are from the wall, the more the seams disappear. Get close up and they can be messy. But no more so than any studio has to deal with. That's what the paint department is for... Best Regards, -t

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