This is a continuation of a discussion that has been taken way off topic in the original thread, here:
Gidday Arthur and Kym
I have taken the colour number readings from the same spot in the image posted below, with no post processing of any description. Open the file in ACR, then change the assigned colour space from PPRGB to aRGB to sRGB and ColorMatch RGB (all 16 bit) and I get the following colour numbers - all listed as 8 bit colour numbers in R-G-B order:
PPRGB - R = 151; G = 63; B = 39
aRGB - R = 188; G = 27; B = 47
sRGB - R = 221; G = 18; B = 42
CMRGB - R = 197; G = 3; B = 30
It is not difficult to see why these numbers will lead to significant colour shifts when printing. I stress again that this is with no PP of any description, merely changing the assigned colour space in ACR.
Closing the image and re-opening using the target colour space and bit depth leads to the same result, so ACR is not re-processing the image in any way, and besides, ACR doesn't work that way.
All the other discussion and reasons you have advanced are not relevant, as no PP has even been done to the image at this stage.
This is the image. It has been converted to sRGB-8 for web display. The point measured is to the right and down from a small spot of sap shown larger and circled in the second image.
Note that placement of this point can be reliably replicated by placing the ACR magnifying glass with cross hairs such that the 10 o'clock position of the cursor just touches the sap spot.
I have printed this image dozens of times (about 25, IIRC ... ), using all the permutations and combinations of colour parameters and without any other editing whatsoever. The differences between the results are stark, and do not require turning the print over to see what colour space and other parameters were used.
RGB colours are made up of a mix of the R,G, and B colour numbers. While these should be shown as 16 bit colour numbers, I find these far less intuitive than using 8 bit colour numbers for reference purposes in ACR. I use 16 bit colour numbers for my web site colours, and it is more than just painful! The precise mix will alter the final colour. The colour numbers quoted above indicate a very large shift in the colour of that spot on the image given as an example. I have measured many, many points on this image (and many others), before arriving at my conclusions and my work parameters. I actually do almost no PP to my images ...If you had a problem in your greens, then it could be understandable that you're having green colour issues.
But from a technical standpoint, the difference in the red and blue channels between sRGB and aRGB are insignificant enough that there is no difference.
See above re the mix of colour numbers.Where aRGB extends beyond the bounds of sRGB's ability to reproduce colours is really only in the green channel(a quick look at those colourspace triangles will confirm this!
So you are already using aRGB, not sRGB, for printing?I've done both and have used both, and the printer(company) I've used has advised me on what colourspace to use for the appropriate situation.
He's happy to print 'accurately' in sRGB, but does recommend to use aRGB .. which is more a a precautionary method to print colours nicer.
I once had a large image that we assessed that would print best if set to the aRGB space .. even tho I shot the image in sRGB, but this print had a lot of green(dark green grassy) areas.
On no other image I've presented to him has he commented that it needed aRGB .. but I did so simply to maintain a standard .
That is, my for this printing company is to edit the images I've getting them to print will always be set in aRGB.
It is when she has posted images with an aRGB colour space on the web.Kym's comments are a very important aspect .. don't convolute yourunnecessarily, which can produce worse results than you're trying to achieve!
And to reiterate(again) the discussion on colourspace here is not within the scope of assisting the OP!
2) As to expense, a decent P-IPS monitor costs about the same as a 1.4x teleconverter. It provides many benefits other than "just" displaying an aRGB colour space - viewing angle, even illumination, portrait/landscape modes, height and angle adjustable stand - that cheaper montiors usually do not provide. The Asus PA246Q monitors I bought also provide a deeper bit depth - 12 bit colour lookup table (LUT) with a 10 bit panel, if connected using either a dual DVI or HDMI connection to the video card.
Agreed. This is extremely important regardless of colour space or bit depth used. However, it is not a zero sum game ... One needs to have a good quality monitor, AND one needs to calibrate one's video card. Both are very important.A much more important investment is having a calibrated monitor.
My reds (and lots of other colours ... ) are not an issue when I use a PPRGB-16 colour space. As I have written before, aRGB-16 is the safest colour space; PPRGB-16 is the best colour space - IMO.As AK said if your reds are an issue I'd be looking elsewhere for a solution.
I note that much of the photography here is of either birds or landscapes. While I have an interest in these genres, my photography ranges over a far wider scope than these two subjects. Many of the things I photograph contain man made materials, and many these have far wider colour gamuts than the natural world (as a very, very general rule ... One has only to look at the colour gamut perceptible to either a dragon fly or a mantis shrimp to understand that the natural world has a very broad colour gamut indeed!).
I want to be able to reproduce those colours accurately, and my un-convoluted work flow does that very well, and has done so for many years. My touchstone of colour accuracy is to compare the print with the real world object in as close to the original lighting conditions as possible.
If anyone is perfectly happy with using an sRGB colour space, far be it from me to proselytize them about switching to what suits me and my photographic aims.
sRGB will not reproduce the colours that match the real object in the real world. Neither will aRGB or PPRGB, but they come a great deal closer to this than does sRGB. Let's not talk about ColorMatch RGB, it is a bad joke.