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  1. #11
    Junior Member

    Re: Faithful Color Reproduction

    Quote Originally Posted by WayneF View Post
    If the goal is correct color, as opposed to tweaking to enhance colors, then no, it does not matter what color clothes or which people are sitting there. The WB goal is to make a white card actually come out white (don't position it so other colors can reflect onto the card - just the direct light only). When achieved, and the card is accurate, then all other colors will be shown as they are too, also accurate. You will have matched WB to the actual lights color.
    The goal is definitely to correct the image to accurately represent the colors we worked for.

    Yes, if you don't change the lighting as you go, I think correcting the WB of the yarn will work fine. I think it is the only chance. OK, more crude tries (using only camera WB settings) can get halfway close, just never quite precise.
    Immediately after reading about white balance, then shooting using a custom white balance setting on his D40, we noticed much improvement in some images, but others that seemed unaffected. At first, we looked for relationships in the colors that were difficult. We theorized that certain colors were more difficult to get right; yellow is more difficult for some reason, but I don't know if that's a WB issue or not. Eventually, we found that many reds, oranges & especially yellow solids, and some variegated yarns using analogous colors, color wheel neighbors as it were, were the difficult skeins to bring to accurately represent the colors in the yarns. I'm anxious to try this using raw, a white card, and the additional smarts we've picked up from you. Waiting for a battery.

    But if seeking most accurate color, I would not use fluorescent lighting, which may or may not be OK, but that is another issue. Incandescent, flash, or sunlight are fine. Don't mix them however, use one type of light source.
    Incandescent, then, seems the more practical for us, but with time & available cash at a premium, this is a variable I'd like to check off the list without doing a lot of experimenting to find it. Should I look be looking at wattage, at color, at (do they even still use) lumens? If so what sorts of values am I after?

    Is it Adobe Raw software? It sounds like you are using a JPG file instead of a Raw file. That's what they do.
    Yes, Adobe Camera Raw. I didn't know I even had it until your video showed me how to access it through Bridge. And it was a jpg I tried; I haven't made a raw file yet to play around with.

    Lossless editing:
    Remember how Edith Bunker's facial expressions changed as she came to an understanding something? I caught mine doing that as I read your lossless editing explanation, including the answer to my question about shifting.

    I'm going fast, I hope it makes sense.
    Not too fast; it is making sense. I'm only mildly frustrated that I can't try this stuff out until the battery arrives; hopefully, that'll be Saturday.


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  2. #12
    Junior Member

    Re: Faithful Color Reproduction

    Quote Originally Posted by hark View Post
    I calibrate my computer monitor. These types of devices generally allow more accurate color reproduction so you should be able to view any differences between the real colors vs. the colors in your photos. From there you can tweak your colors using some type of editing software.
    Hark, when you mentioned this Spyder4pro calibration system, it was the first I'd heard of it, I think. And Wayne, in your excellent article about WB correction, you said

    It is a good plan to start with a monitor calibration system, to be sure you see things right. I use an old DataColor Spyder 2 Express (most basic version), which seems more than enough. Its sensor reads known colors and intensities on the monitor screen, and adjusts video response so that they display as expected.
    The Spyder4 can be had for $79 incl. shipping. The knowledgebase at datacolor.com indicates Windows 8.1 compatibility. After 10 years with XP, I moved to 8.1 about 6 months ago.

    The Spyder2 is still available in used condition, and I found 3 at or below $35 incl. shipping. However, the datacolor.com has 2 drivers that look like they might be suitable for this device, but neither of them have been updated since 2006, and 2008 respectively, and no mention of a Windows OS beyond Vista is made. If I can use the Spyder2 on my 8.1 (64 bit) box, I think I'll pick one up. If I have to get the Spyder4, I'll probably hold off for now. So, two questions:

    1. Do you know if the older Spyder2 drivers can be used in successfully in 8.1, or if the Spyder4 drivers will function in a Spyder2 device?

    2. If not, do you know of a free or low priced, entry level software-only solution for monitor calibration that will improve my confidence in the color reproduction on my monitor?

  3. #13
    Senior Member
    Software only probably won't boost your confidence as it's relying entirely on you eyeballing the correct values. Well, that is, unless you think you're God-given gift to light spectrum analysis. I, for one, don't have this type of self-confidence.

    Oh, thinking about that bit where you see too little or too much variant on similar colors : jpegs, unlike raw, are affected by a myriad of contrast, saturation, sharpening and similar in-camera effects (picture control, advanced -_-lighting, etc.) that may play Havok with color rendering.
    Last edited by PaulPosition; 06-28-2014 at 03:34 PM.
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  4. #14
    Senior Member
    WayneF's Avatar

    Re: Faithful Color Reproduction

    Quote Originally Posted by Dyers View Post
    Immediately after reading about white balance, then shooting using a custom white balance setting on his D40, we noticed much improvement in some images, but others that seemed unaffected. At first, we looked for relationships in the colors that were difficult. We theorized that certain colors were more difficult to get right; yellow is more difficult for some reason, but I don't know if that's a WB issue or not. Eventually, we found that many reds, oranges & especially yellow solids, and some variegated yarns using analogous colors, color wheel neighbors as it were, were the difficult skeins to bring to accurately represent the colors in the yarns. I'm anxious to try this using raw, a white card, and the additional smarts we've picked up from you. Waiting for a battery.
    Fluorescent is tricky, not a full spectrum, which means some colors are simply missing. This makes illuminating those subject colors be a real problem. There is a CRI (Color Rendering Index) number on some fluorescent bulb packages, good ones are around CRI 90-92, which means the color spectrum is 90% as good as incandescent (many fluorescent are much worse). So then, most colors are OK, but there can be exceptions. The white card can match colors, but it cannot fill in missing colors. So if fluorescent, specifically look for high CRI lamps. If you have fluorescent bulbs where your wife chooses her clothing colors, she absolutely wants high CRI bulbs there.

    But incandescent is better color, and no problem, but there are cool, warm, daylight type of bulbs, they should all match (wattage and age/hours too). And it is just me, but my notion is that the daylight type using phosphorus coatings are also not as fully complete spectrum. Nothing wrong with regular incandescent, if using the white card to match them.

    Color can always be a problem. And exposure can shift colors a bit. Yellow and red are bright, esp after shifted to daylight or flash WB, and it is not uncommon than one of the three channels is clipping somewhat. This can change things, the color we see if clipped. Just saying, pay attention to the THREE CHANNEL RGB histogram in the camera (NOT the one single gray histogram) as you setup your exposure, and don't clip any channel on the right. Not saying it should be intentional, but a slight underexposure seems no big deal in Raw, we just boost it back up as desired. We can do that to all in one click too. But we can never recover clipped data.

    EDIT: Raw files have no WB in them, so this shift is not yet done, but will be done later. But the camera LCD and histogram are showing a JPG which is embedded in the NEF file, which has the camera WB settings in it, so it is showing that final WB. So, the camera WB setting, which does not affect the Raw file, but should be approximately correct value anyway, for judging exposure on the camera histogram. And so you see a better LCD picture. And, Adobe Raw will try to use that WB setting in its AS SHOT result. You can do better than AS SHOT however, later.

    Incandescent, then, seems the more practical for us, but with time & available cash at a premium, this is a variable I'd like to check off the list without doing a lot of experimenting to find it. Should I look be looking at wattage, at color, at (do they even still use) lumens? If so what sorts of values am I after?
    Portraits of humans with incandescent lights are problematic. Not the color, but because the lights are fairly dim, and we end up with the lens wide open at 1/30 second, trying to make it work. (modern ISO helps today). But we'd like a shutter speed of say 1/100 second to stop motion of the subject squirming, and maybe we want f/11 for depth of field, esp on your yarn. Flash is greatly more practical to do that, brighter for human subjects.

    But the yarn is inanimate, and any slow shutter speed, even one full second, is no big deal at all (assuming camera is fixed on a tripod). So brightest lights are unnecessary, optional. A bigger concern would be the "lighting". A light bulb is a small harsh light (dark sharp shadows), but large lights (like an umbrella, maybe 3 feet diameter) casts nearly shadowless soft light. This could be any white reflector, reflecting a big surface lighted area back to the subject (from many directions, simply because it is large, and near).

    The problem with incandescents today is finding them to buy. Some CFL lamps are real problems, color wise. Amazon still has some various incandescents, and also I think 150 watt size may still be manufactured.

    There are special photoflood incandescent bulbs for photography, high watts and short life, bright and usually 3400K for special older indoor film, which was important in 1960, but really no longer important for digital WB since we can match most situations now. But if you did want high power, this is one way. (high power is hot and uncomfortable of course).

    But I think a longer shutter speed is of no concern in your use.
    Last edited by WayneF; 06-28-2014 at 05:06 PM.
    Thanks/Like Dyers Thanks/liked this post
     
    Wayne

    Flash and Camera Fundamentals We Should Know

  5. #15
    Senior Member
    WayneF's Avatar

    Re: Faithful Color Reproduction

    Quote Originally Posted by Dyers View Post
    1. Do you know if the older Spyder2 drivers can be used in successfully in 8.1, or if the Spyder4 drivers will function in a Spyder2 device?
    The Spyder2 driver version 2.3.6 works fine in 64 bit Win7. I don't know about Win8, but I thought the drivers were the same?

  6. #16
    Junior Member

    Re: Faithful Color Reproduction

    Quote Originally Posted by PaulPosition View Post
    Software only probably won't boost your confidence as it's relying entirely on you eyeballing the correct values. Well, that is, unless you think you're God-given gift to light spectrum analysis. I, for one, don't have this type of self-confidence.
    I think you're right about a software-only solution not boosting my confidence. The attempts I've made at using them left me rather jaded about monitor calibration. This thing seems like it might be worth trying, and it has a lot to do with the recommendations you all have made.

    Oh, thinking about that bit where you see too little or too much variant on similar colors : jpegs, unlike raw, are affected by a myriad of contrast, saturation, sharpening and similar in-camera effects (picture control, advanced -_-lighting, etc.) that may play Havok with color rendering.
    My N90s had auto settings, but with the exception of auto focus, I didn't ever learn to use them. Honestly, I don't know why raw never caught my attention before, but it seems like it's going to be one of the tools we'll be using to get the accurate color we need without so much tedious time spent trying to manually correct color with the tools you just mentioned.

  7. #17
    Junior Member

    Re: Faithful Color Reproduction

    Okay; that helps a lot. I think you've given me enough information to be able to find the bulbs I need; lower power to reduce heat, and to avoid the more expensive fixtures one needs to use with higher wattage lamps. Not going to concern myself with color temp. ratings, nor with designations such as "daylight" because I can correct whatever color the bulb introduces. Thank you very much.

    You mention color clipping. I've heard audiophiles talk about clipping for 35 or more years, and while I have a vague idea of what that sounds like, I wouldn't want to have to try to explain it to anyone with the little bit of understanding I have. Used in this context, I'm kind of clueless. The first time I read about it's use in this way was in something you wrote, I believe in the article you referenced early on. What happens with color clipping; what would I be likely to see?

    We sometimes need to photograph rather small, very reflective parts for sewing machines. With these, the color isn't as important as with the yarn, but we were still having lighting issues with them; intense hot spots, strong shadows, and harsh reflections. We built 3 frames of wood over which we stretched several layers of cheese cloth. These are only about 300mm square, but are fairly deep, about 75mm, and this allows them to stand in most any configuration to diffuse the light source(s). The yarn isn't reflective, and possibly due to the use of multiple light sources, and/or the black background, there isn't much shadow to contend with. What I do get are some hazy reflection of the light that bounces off the yarn on the black Formica we use as a seamless background, and I like that a lot. We do use a tripod for all of this work, and also the camera's self timer to avoid any camera movement when the shutter is released. An aperture of f11 is typical, as are very slow shutter speeds.

    The Spyder2 driver version 2.3.6 works fine in 64 bit Win7. I don't know about Win8, but I thought the drivers were the same?
    Which drivers do you suspect are the same; for Win7 & Win8, or for Spyder2 & Spyder4?

    This has been enlightening, and immensely interesting. I didn't anticipate so much detail, so much individual attention in your responses, and I am very grateful for it. I want to get to work and put some of it to the test. I'll write more after trying out some of the yarns that have been more challenging so far.

  8. #18
    Senior Member
    WayneF's Avatar

    Re: Faithful Color Reproduction

    Quote Originally Posted by Dyers View Post
    You mention color clipping. I've heard audiophiles talk about clipping for 35 or more years, and while I have a vague idea of what that sounds like, I wouldn't want to have to try to explain it to anyone with the little bit of understanding I have. Used in this context, I'm kind of clueless. The first time I read about it's use in this way was in something you wrote, I believe in the article you referenced early on. What happens with color clipping; what would I be likely to see?
    Clipping is the single most important factor about monitoring exposure (because it cannot be corrected).
    Clipping just means overexposure, but in a specific most-harmful way:

    Adding additional exposure (in camera, or with ACR Exposure slider) moves the histogram data right (brighter).

    When the right end of the data reaches the right end of the histogram, it can go no farther, there is nothing beyond 255 (8 bit numbers can only range from 0 to 255... 8 bits can count no higher, 256 requires a 9 bit number, which JPG does not have). So the right end just hangs there clipped at 255. Additional exposure just piles up more pixels, clipped at this right end at 255, and we see a tall spike develop in the histogram data right on the 255 end. That spike denotes clipping (data piled up at the 255 end).

    We can have overexposure (say of dark colors) that does not reach 255, and this can be backed off and corrected. No actual problem, at least not in Raw. In fact, some intentionally do this, and call it Expose To The Right, as a way to reduce digital noise. When we shift the data back down, we shift the noise down too.

    But if clipped at 255, it cannot be corrected or restored, that data is gone (clipped, converted to 255 when it should be higher). Mild cases probably only clip one of the RGB channels, but this still changes color, the colors are not what they should be.

    You can see this happen in ACR, in a test, just boost exposure too much with the Exposure slider, more than enough to reach the right end.

    (I should shout IMPORTANT here... ) When there is actual concern, in ACR, you can see which pixels are clipped or clipping, by holding the keyboard ALT key, and touching and holding the ACR Exposure slider with the mouse, and the screen image turns black, except for the pixels that are clipped. As you move the slider, you see more pixels be clipped. Adobe Levels works the same way. Now you know what is clipped, or what you are clipping.

    If this test case clipping is something like a human face portrait, probably the face suffers early clipping. The skin color becomes white and pasty color, with no detail in it.

    But there are don't care cases when a little clipping may not always matter (in unimportant image areas, maybe a glare on a table surface), and benign clipping is one way to increase brightness and/or contrast (there are better ways).


    We cannot restore clipped data in the original image (if it is clipped and gone), so it is important to monitor this histogram in the camera, at the scene at the time, when it can still be corrected and repeated. It merely takes a glance. The camera shows one single gray histogram, which is useless to show clipping. It also shows three RGB channels, which is where it's at. If any of the three RGB channels show clipping (the spike touching the right end), back off on camera exposure. Red flowers in sunlight typically clip a little in the red channel.

    Here is an example of that: Two types of Histograms



    We sometimes need to photograph rather small, very reflective parts for sewing machines. With these, the color isn't as important as with the yarn, but we were still having lighting issues with them; intense hot spots, strong shadows, and harsh reflections. We built 3 frames of wood over which we stretched several layers of cheese cloth. These are only about 300mm square, but are fairly deep, about 75mm, and this allows them to stand in most any configuration to diffuse the light source(s). The yarn isn't reflective, and possibly due to the use of multiple light sources, and/or the black background, there isn't much shadow to contend with. What I do get are some hazy reflection of the light that bounces off the yarn on the black Formica we use as a seamless background, and I like that a lot. We do use a tripod for all of this work, and also the camera's self timer to avoid any camera movement when the shutter is released. An aperture of f11 is typical, as are very slow shutter speeds.
    Your diffusion screens sound like a good thing.

    Which drivers do you suspect are the same; for Win7 & Win8, or for Spyder2 & Spyder4?
    I guessed maybe Win7 and Win8 can use the same driver? I don't know about Spyder4, but would not expect that compatibility. I don't know the difference, but the cost of the new one is not extreme. I just use the old one because it performs very well.

    IMO, there is not a big difference, but there is a difference, and calibrated is better. LCD monitors are normally too bright for photos, and calibrating can bring that back down, so the images you adjust will look better elsewhere. I also set the cameras LCD Brightness to -1, to make it better match the computer monitor.

  9. #19
    Junior Member

    Re: Faithful Color Reproduction

    Faithful Color Reproduction
    Your comments on anything you see here that could be improved are welcome.

    RAW
    light source: (two) 150w Soft White Standard Incandescent Lamps in Aluminum Clamp Fixtures rated to 150w
    @ 40cm to 45cm from the subject.
    Faithful Color Reproduction-skein2raw.jpg Faithful Color Reproduction-skein3raw.jpg Faithful Color Reproduction-skein4raw.jpg

    After WB Tool
    Faithful Color Reproduction-skein2wb.jpg Faithful Color Reproduction-skein3wb.jpg Faithful Color Reproduction-skein4wb.jpg

    After RAW Correction
    Faithful Color Reproduction-skein4raw_correct.jpg Faithful Color Reproduction-skein3raw_correct.jpg Faithful Color Reproduction-skein2raw_correct.jpg

    The images in the After RAW Correction row are as close as I can come to accurate, and they're remarkably close. I could bring all the images (3 different shots each of all 3 skeins - this is only 1 of each) into white balance at once, and that only took a few seconds. I could then correct each group of 3 images for each yarn for color accuracy, though I cropped and retouched each image with the Retouch Tool individually. Getting from the middle row to the last row took about 70 minutes, though much of that time was spent experimenting with the various tabs full of tools. I think that will be much reduced when I have a better idea of what each does, and when to use them. This red-orange is the most accurate I've ever come with a shade in it's range. It's still a tad yellower than the yarn itself which is slightly rustier; the green sliders had no effect, and that's all that would have been required to tone down the orange ever so slightly. I chose the two greens because I had been unable to correct their color in a way that distinguished the two greens. The yellows in the 3rd image are right-on. I was unable to get this yellow & this green using Photoshop tools when the skein was photographed under daylight CFLs.

    Peace,

    Dave

  10. #20
    Senior Member
    WayneF's Avatar

    Re: Faithful Color Reproduction

    Faithful Color Reproduction
    Quote Originally Posted by Dyers View Post
    Your comments on anything you see here that could be improved are welcome.

    RAW
    light source: (two) 150w Soft White Standard Incandescent Lamps in Aluminum Clamp Fixtures rated to 150w
    @ 40cm to 45cm from the subject.


    After WB Tool
    Faithful Color Reproduction-skein4wb.jpg

    Thanks for including all the data. Makes understanding easy.

    I fear you are seriously clipping (overexposing) the white card, to make it unusable. See the histogram? That bright spot at far right is the white card. Clipping it like this removes the color cast you are trying to see. See it in AS SHOT histograms... the red and green components of it are clipped there. That clipping corrupts the color of the card.

    I suppose your lights are high in front, making the white card the nearest thing to the lights, and it is already the brightest thing. I would turn the camera horizontal, and put the white card a little behind the yarn (farther from lights), off to one side to allow cropping it out (a little below that bright spot maybe).

    If it has to be this much closer than the yarn, then that might be the one place a gray card has advantage (a WhiBal card is good). Gray is harder to clip (its only advantage, white is likely more accurate, and more direct to the point of White Balance).


    After RAW Correction
    Faithful Color Reproduction-skein3raw_correct.jpg

    But the picture seems unpleasantly dark, unlike any catalog I ever saw. Catalogs are bright. Feels like straining to see the yarn here, in the dark. Needs more exposure (but watch out for the white card). Could simply crank exposure up here in Raw.

    Except the red yarn is probably bright enough (holding ALT key while increasing exposure shows its highlights start to clip real soon, at least on top. Maybe the lighting could be made more even? Or maybe the dark background is not the best choice. It does hide the shadows cast by the lights, but maybe lighter gray, or even white? I would experiment with it once.

    And notice that each color of yarn changes the shutter speed of your camera exposure. Yet the lights are the same, and the setup is the same, exposure would be expected to be the same. That is what reflective light meters do (which is not a plus). But there is no reason the same one correct exposure would not be correct for all. You could use Manual camera exposure, which after you experimented to get it right, which would stay the same for all.

    Don't overexpose, esp including the white card, but slight underexposure is no big deal, since Raw exposure can simply boost it back up. That boost is about the same effect as boosting ISO.


    Your ACR screen shows color profile is Adobe RGB. But all computer monitors and web screens (and online printing places, and your default printer driver) standardize on sRGB. This is a biggie. Just click that line (below the ACR picture) that says Adobe RGB, and change it to sRGB. This one click affects all future JPG outputs from ACR. You will also want to change it in Photoshop menu: Edit - Color Settings (so it won't fuss about the difference).


    I was unable to get this yellow & this green using Photoshop tools when the skein was photographed under daylight CFLs.
    Right, seriously avoid CFL when color is a concern.
    Last edited by WayneF; 07-01-2014 at 05:27 PM.
    Thanks/Like Dyers Thanks/liked this post
     
    Wayne

    Flash and Camera Fundamentals We Should Know





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