I haven't bought a professional SLR camera to take pictures of traditional oil painting, but I have a theory of a color value chart I could create with the particular camera I'll buy.
If I paint out all my tube colors and take a picture of it with the camera, I can then put the picture in Painter, use the picker to choose those colors and determine the values. Digitally picking and painting out all the colors from the picture, I can then make the chart below. The point would be, I can determine exactly what values the camera see's. In theory there should be little rework of colors and values in photoshop/painter when I take a picture with the SLR camera.
I first started making the chart to really try to figure out where exactly the values of my particular paints were located in value. A lot of the colors are hard to determine the values, for example 27% (does it belong in the 2 value range or the 3?). (note:*For this particular chart I used a scanner.*)
Does this sound like a legitimate way of determining the values of paint colors?
It would be interesting to see how your results compare with your visual estimates. The values you get will depend on the exposure and contrast, so you'll need to photograph your paints in even lighting alongside a Munsell grey scale to calibrate your results. The only measure of value suitable for your purpose is L of Lab, available in Photoshop but not Painter.
I would recommend matching your grayscale value to the color swatch sample as you've painted it instead of doing it within a digital program. That way you're making your comparison under real-world conditions and not with digital approximates of those colors. You could then treat the camera and grid as a way of recording your findings.
briggsy - Thank you for replying. I feel like I have real problems trying to determine the values of color, visually (the reason for the chart). I have made a value scale from the same paint with ivory black. Comparing it, to me, this Cad. Yellow Med. looks as if it would be a value of about 7. I think this is only because of the chroma though. .... I did scan this value scale also, but visually, my idea's of each of the values, like halfway between 0 and 10 should produce 5, then halfway between 0 and 5 produce 2 1/2, etc. were off using the program (if i remember correctly, like 57%). So trying to figure out what are the correct values in black and white is a problem. .... Thanks for the information, will try the L lab. Appreciate it.
Thanks, dbclemons, I believe this comment I made to briggsy also applies. Trying to figure out what the exact values are with your particular paint/brand/tinting strength, ect. with how you send the final format to the customer (digital) is what I'm trying to figure out. Thanks for the response.
Bowlin, the problem is that what Painter is showing you is the saturation, not the value (check out briggsy's site for info on the complicated interrelationship between saturation, value, and chroma). I took your chart into Photoshop, desaturated it, and also turned it into grayscale to show the difference. Did you ever pick up a copy of the Munsell student book? Attachment 554537
Elwell - Thanks man, I really do appreciate it. That makes so much more sense. You can see in the picture below I was using the color picker in Painter to determine the value (for anybody that was curious). I had always assumed that desaturating the colors WAS converting them to greyscale (sometimes it's the simplest things that will confuse you).Thanks for clearing that up.
Yes, I did get the Munsell student book and have done the color charts, simply comparing one value to another of the same color, I feel confident about. And using the Reily book you suggested to learn how to mix the color you want helped immensely!! It's finding the right colors to put next to the other colors that confuse me because of the colors saturation, I believe. So just trying to determine my palette colors seemed to be the place to start.
Also, it feels like I can only determine the lighting so much with pencil for tight sketches. So when you convert this value study to paint, you have to elaborate and refine a lot, because paint has so much more value range. Causing a lot of confusion.
the reason you get different results in painter and ps is that there are many, many different ways to judge the values of colors and i would also suspect that different ppl see them differently as well.
desaturated in painter judges colors to be linear- that is pure yellow is the same value as pure blue, which of course your eyes will tell you is not true.
photoshops convert to greyscale takes the change of value into account and so pure blue is very dark and pure yellow is very light, whether or not this is 100% accurate doesnt matter, it does however reinforce the contrast created between say yellow and blue and will make the greyed version more true to the colored original in terms of contrast and therefore value pattern.
i never use the desturate in painter because it will destroy your contrast in stead i use this plug-in and you can if you want set the values manually - but i don't find it necessary to do so , as far as im concerned the photoshop option is close enough not to destroy the value pattern.