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  1. elkcub

    Photo Method for Showing Color Bias and Light Transmission

    Yup, that makes sense. The calculators can be scaled differently within the same measurement framework. But, I suspect that the computed GRB transmission values were also distorted by Henry's iPhoto correction of the "exposure". This may very well have had a disproportional impact on...
  2. elkcub

    Photo Method for Showing Color Bias and Light Transmission

    Hi Henry, A basic question, I think, is the validity of what we're doing. By that I mean, how do our inferences from simple pixel values correspond with refined spectral transmittance measurements of luminous flux? At best, I would guess they are a gross approximation, which hopefully retain...
  3. elkcub

    Photo Method for Showing Color Bias and Light Transmission

    Henry, Here's what I get: Background 229, 228, 232 C= Sum(RGB) = 689 UL 219, 221, 220 Trans= 660/689 = 95.79% 8x56FL UR 218, 220, 216 Trans= 654/689 = 94.92% 7x42FL LL 218, 218, 218 Trans= 654/689 = 94.92% 8x42 Ultravid LR 216, 216, 216 Trans= 648/689 = 94.05% 8x42 FL Again...
  4. elkcub

    Photo Method for Showing Color Bias and Light Transmission

    Hi Ron, I think you're right on track. You expressed the observed R, G, and B values from the binocular-plus-camera as a proportion of the R, G, and B values obtained from the camera alone. When these proportions are taken of pure white (255, 255, 255) it models the binoculars' (pure) color...
  5. elkcub

    Photo Method for Showing Color Bias and Light Transmission

    Ron, I'm having a senior moment. Don't follow how you arrive at shift values in RGB. I understand the H-shift in degrees when comparing two hues. Ed
  6. elkcub

    Photo Method for Showing Color Bias and Light Transmission

    With reference to Post #21, as Ron mentioned the various areas are not quite uniform. The following RGB readings, therefore, are estimates of an average value. Four section panel: Background 227, 228, 232 (blue bias) Upper Left 216, 216, 216 — 8x42 Ultravid Lower Left 215, 215, 215 —...
  7. elkcub

    Photo Method for Showing Color Bias and Light Transmission

    Ron, Since you have the 8x20 Swaro, Ultravid, and LX L, — which do you like best? In particular, I'm interested in the Ultravid vs. LX L. I've tried to take photos of various bins on a light table with 5000K bulbs, but so far nothing comes out as well as Henry's. Basically, I just get...
  8. elkcub

    Photo Method for Showing Color Bias and Light Transmission

    Ron, My impression was that a 3mm beam was used. But, I speak no German, so it's all Greek to me. What and where is the on-line calculator? The Mac has quite an extensive ColorSync Utility, which provides all the tristimulus values and rotation matrices. I agree, that hue, saturation and...
  9. elkcub

    Photo Method for Showing Color Bias and Light Transmission

    I'm satisfied that RBG values remain unchanged (numerically) when I modify my computer's screen profile. Although the PowerBook G4 that I use can be changed from its default "Color LCD" setting to "CIE RGB" or "sRGB" (and many other profiles), the visual impression of subtle color differences...
  10. elkcub

    Photo Method for Showing Color Bias and Light Transmission

    Hey Ron, Sorry to take so long responding. Your explanation hit the spot! :t: Ed
  11. elkcub

    Photo Method for Showing Color Bias and Light Transmission

    Ron/Henry, Looks like we get about the same RGB readings, -- see my post #5. What is your motivation for converting to CIE values? After taking a spot reading from a screen area (or an area average), it seems to me that then creating a uniform color swatch with these values is about the best...
  12. elkcub

    Photo Method for Showing Color Bias and Light Transmission

    Henry, In post #1 the background RGB is (225, 224, 228) -- slightly blue the center of the inner box is (217, 212, 198) -- red-green In post #4 the values are: Background (220, 219, 223) -- slightly blue, and 220.7/225.7 = 98% of the background in Post #1. Upper left (216, 213, 197) => 94.8%...
  13. elkcub

    Photo Method for Showing Color Bias and Light Transmission

    Oh, I posted on the other thread a few minutes ago, so I'll just copy it here. At least for RGB values, Microsoft and Adobe software produce the same screen results. The Art Director's Toolkit can be obtained here for Mac, but Windows is also available...
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