Question 1

Where can I find the color data for each of the patches? The instructions that come with it say to look on the back of the card. Not exactly accurate

Accepted Answer

I found the web page of the vendor through web searches, http://rags-int-inc.com/.  This is mainly a blog.  The data you need is on an PDF file that you can get there if you hunt for it.  The data I have is:
No.  Color  (BCS)
1:  White (97,0,1)
2:  Gray 73 (73,0,0)
3:  Gray 62 (62,0,0)
4:  Gray 50 (50,0,0)
5:  Gray 38 (38,0,0)
6:  Black (23,0,0)
7:  Red (48,59,39)
8:  Yellow (92,1,95)
9:  Green (64,-40,54)
10:  Cyan (57,-41,-42)
11:  Blue (18,-3,-25)
12:  Magenta (49,60,-3)
13:  CIE TSC 01 (41,51,26)
14:  CIE TSC 02 (61,29,57)
15:  CIE TSC 06 (52,-24,-24)
16:  CIE TSC 08 (52,47,-14)
17:  CIE TSC 09 (69,14,17)
18:  CIE TSC 10 (64,12,17)
Here, I discerned that the numbers in parenthesis are LAB slider numbers, an alternative to RGB used in photo editing software such as Photoshop, PaintShop Pro, Picasa, etc.  The numbers are Lightness, A channel, and B channel (bear with me a bit here).  The Lightness channel is ideally subject reflectivity to all colors, 0 to 100, and measures brightness as would be seen in an ideal B/W print.  The A channel is a green-neutral-magenta color slider, -128 for max green, 0 for grays, and +127 for max magenta.  The B channel is a blue-neutral-yellow slider.

Once I had converted all these to RGB but I can't find that data table on my computer.

The way to use the color card is to take as well exposed a photo as you can, then load the image in photo editing software.  Use the eyedropper tool to capture the center of each color patch and look at the color in LAB space.  The numbers should be similar to those given in the table.  Too much variance means that exposure or color balance can use some work.  HINT:  For gray patches, the B channel numbers correlate with color temperature a lot, and the A channel numbers tell you how white the lighting is.

Question 2

Is this a reflective surface like their other color charts?

Accepted Answer

5not quite sure what you're asking, everything besides maybe black velvet is reflective.  the card is 18% grey on one side.  the oher side is as shown.  both sides i would say are matte finish semi-rigid plastic.  the only two things i see "wrong" with the product is a. its size (5x7) and the provided card holder/stand.  the stand is not strong enough to support the weight of the card which is rather amazing, but true.  but, at about 1/10 the price of the real mc coy, i am pleased.

Question 3

What application are you using to match the color profile within Ps/Lr?

Accepted Answer

I am actually using the grey card to set the camera correctly before the shoot.

Question 4

Does this say how many f stops the colors are from 0?

Accepted Answer

When you say 0 I assume you mean complete black. That depends on the amount of light in the area you’re shooting and the latitude of the camera/settings. If you expose correctly, the 18% gray part of the chart should be right in the middle of your exposure (if you have a histogram that shows all of the light in the frame, that part should be dead center). As far as the luminance and perceived brightness of the colors (which I think was your question), they are all different. The color closest to gray’s exposure on this chart is probably green, even though it looks brighter. Try taking a screenshot of the chart on your device and bring down the saturation all the way and you’ll get an idea of what I mean.  There is a page that you might find useful here: https://www.scantips.com/lumin.html

DGK Color Tools WDKK Waterproof 18% Gray Color Chart and Warm Card Tool Kit with Stand and Case

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