Re: Colorsync-users Digest, Vol 13, Issue 79
Re: Colorsync-users Digest, Vol 13, Issue 79
- Subject: Re: Colorsync-users Digest, Vol 13, Issue 79
- From: Ben Goren <email@hidden>
- Date: Thu, 17 Mar 2016 08:16:46 -0700
On Mar 16, 2016, at 8:47 PM, Chris Cox <email@hidden> wrote:
> So you admit that your previous claim was wrong.
> ACR and DNG have the capability,
ACR? No. It's useless for colorimetric copy work. It has no objective means of setting exposure nor channel balance. Indeed, those sliders may well be great for artistic expression, but they guarantee that you'll never ever even in principle get balanced channels and to-the-0.01-stop correct exposure.
And ACR only supports a fixed and very small set of output spaces -- with no option to output to the camera's native space tagged with a suitable profile. And none of the supported spaces make especially good working spaces, save for sRGB for Web output, meaning you've got another color transform before you get to the data.
I could keep going, but it would obviously be very bad for your blood pressure.
DNG could maybe be kludged if you had a suitable non-ACR RAW developer that spoke DNG. I've heard rumors that CaptureOne might be such a tool, maybe. Anders's tool is mostly useful for those wanting to use Adobe's artistic rendering tools but with a more accurate starting point. I still wouldn't recommend it for colorimetric copy work.
I still think you owe it to yourself to examine why you're so upset at the thought that Adobe products, which are excellent for their designed purpose, aren't useful for a purpose they were never designed for. Is your ego really that bruised to learn that a farmer needing to harvest thousands of acres of wheat isn't interested in buying your beloved Lamborghini? That he doesn't care that the Lamborghini can cross a prepared track the length of the farm in under 30 seconds but his combine harvesters take a couple days to finish the job?
> In Photoshop, if you
> blend in a gamma 1.0 document,
First, that the default is anything other than gamma 1.0 blending demonstrates that whoever wrote the code doesn't understand what gamma is or what it's for. It's nothing more nor less than a form of data compression, a more efficient use of the bits on the disk. Doing color math in a gamma-encoded space is as insane as doing a spellcheck on an uncompressed ZIP file.
And then we've got the problem that gamma _is_ vital for the internal storage, and forcing people to use gamma 1.0 for internal storage just to do correct manipulation of it then opens them up to all the problems that gamma fixes in the first place.
What you've just told us is that Adobe's option is to either accept posterization of shadows or dramatically incorrect blending. And you think this is an acceptable compromise? Indeed, you yourself confirm this:
> Of course, you may also see the artifacts
> that accumulate rapidly if you attempt to use gamma 1.0 blending in an 8
> bit/channel document, which is why most people don’t do that unless they
> work in floating point (32 bit/channel) images.
Right. And it never occurred to anybody at Adobe to crack open a math textbook to learn how to do the proper math on gamma-encoded data, or maybe to do the blending math on the FPU and convert back to integers when done? Or maybe incorporate some code from ImageMagick, an open source project that does the same operations but doesn't suffer the same problems? After all, if Microsoft could get its original TCP/IP stack from BSD, why can'd Adobe get its color engine from similar sources?
> And you are still making broad claims based on very narrow issues (many of
> your own making or misunderstanding).
Sorry, but you yourself are repeatedly pointing out the critical flaws in Photoshop and bragging about them as if they were features, not bugs. It's like the Lamborghini dealer admitting that, sure, the Lambo's elapsed times suffer if the track isn't well prepped, but it's the farmer's fault for not paving the hedgerows and that's no excuse for preferring the combine harvester and thinking the Lambo is an overpriced toy.
b&
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