ray_parkhurst wrote:Can anyone posit why the patch 7 R channel in sRGB is -49?
I'll posit as follows:
Note in the explanatory comments of the spreadsheet: "The count values shown in
RED below are considered out-of-gamut for the particular color space listed." (Emphasis theirs.)
The data are presented as an Excel spreadsheet, and in Excel, an easy way to make a number appear red is to enter is as negative. (No doubt this is due to the roots of spreadsheets--financial accounting--where things like
losses are recorded in red ink, and things like profits in black ink.)
If I were creating such a spreadsheet, my first thought would be to change the formatting for those particular cells to display in red, and record the integer as positive. But whoever created that spreadsheet might know less about Excel than I do and not have thought of changing format; conversely, whoever created that spreadsheet might know more than I do--and for some reason, considered using a negative integer less likely to cause trouble across platforms or alternate spreadsheet readers.
At any rate, by way of a trial, in Photoshop I created two test images: One in Adobe RGB (1998), the other in sRGB. For the Adobe image, I used RGB values as listed--64, 134, 65. The result was a color I'll call "teal," which nicely matches the square on the test subject's far left, one row down from the top. For the sRGB image, I used RGB values 49 (not "-49" which I think impossible), 135, 168. The result is a similar color, but a little bit "more gray"--exactly the sort of result I've seen for out-of-gamut colors improperly rendered in sRGB.
Make any sense?
As for the price of these targets: I don't think it seems out of line when one considers the fully-loaded cost to produce. The targets seem to be hand-made, as precisely as possible, and in small quantities--a perfect recipe for "not possible to produce cheap." In producing items that don't benefit from economy of scale, a good rule of thumb is that the producer needs to sell at least at double his cost to produce, when cost includes materials, a fair wage for time expended in product development, production, marketing, bill-collecting and other business activities, and some price-in for risks taken. Considering all this, $140 (half of $280) strikes me as barely adequate--or even inadequate--to cover these costs. Given the possibility of low sales volume, I question whether the producer will derive enough income to keep this item on the market. If you want one before the producer gives up, I suggest you buy now.
I also don't think $280 is excessive for a photographer with a strong need for this product. Granted, most of us are not that photographer. But if one is being paid, among other things, for very careful color reproduction, and if this product delivers it well, $280 may be a trivial expense. For example, imagine photographing for a broker in the gem markets of India, taking pre-purchase photographs for potential buyers of big-ticket gems, who live on the other side of the world, and who are very particular about a gem's exact color. If this product makes the process significantly less fault-prone, would you scoff at the price?
In my own photography and involvement in wetland science, I've often been called upon to photograph core samples of soil by the hundreds, with the requirement to render soil color at various strata as exactly as possible. This to satisfy critical analysis by state and federal regulators who classify soil types, partly by color. My approach to this has been fivefold: Photograph the core samples in both in raw + jpeg (1) under light from a speedlight of known color temperature (2) with a white color reference included in the shot (3), and also included in the shot, the page in the Munsell Soil Color Book (4) that most closely matches the stratum of most importance. This set of photographs, plus the presence of the Munsell soil book, allows me to calibrate a monitor or print to match the soil reference book and soil samples very well.
Soil color can be an important determinant of historic wetland/upland status of land--an important point under U.S. law. In every case I've been involved in, our level of record-keeping, photographic and otherwise, has made our case solid. Since our Munsell Soil Color Book is part of this work I've known, and since Munsell is related to the color test target in this discussion; and since our Munsell material has placed us in the "good evidence" category, in investigations, and since our Munsell Soil Book resembles, in price, the target currently under question, I'm inclined to say, "Forget the price. Does this target serve a need you have?
--Chris S.