Luminous Landscape Forum

Raw & Post Processing, Printing => Adobe Camera Raw Q&A => Topic started by: Lundberg02 on March 31, 2014, 06:15:59 pm

Title: arbitrary RGB profiles for opening RAW
Post by: Lundberg02 on March 31, 2014, 06:15:59 pm
In response to my question in the Adobe Photoshop Forum, Jeff Schewe, the well known guru, replied that in Photoshop CS6 CC you can add arbitrary RGB profiles to the Workflow Options in ACR.  Workflow Options opens when you click on the blue description of the profile you are opening the RAW file with, at the bottom of the ACR window.
Does anyone know any other RAW file converter that has this option? I have just asked ACDSee tech support about this. It is not apparent that they have this capability in the Mac version. I'm haven't looked thoroughly at any of the others I have yet. You would think that draw or converters based on it would be able to do, this such as GIMP or RAWTherapee.
I have a bunch of iccs I'd like to add, like MaxRGB, PhotoGamut, ECI.
I was able to add iccs to Photoshop 5.1 to use for conversion after opening by going to Library/Application Support/Adobe/Color/Profiles, but I don't see even that capability for ACDSee.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: digitaldog on March 31, 2014, 07:18:56 pm
Iridient Developer should work (Mac only). http://www.iridientdigital.com
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Royce Howland on March 31, 2014, 08:09:08 pm
As far as I can tell, this new feature of ACR is available only when using it within Photoshop CC, not within CS6. But yes, we do now have the ability in the Adobe workflow to convert our RAW files directly into arbitrary colour spaces.

Though I don't use it, I believe Capture One can do this as well:
http://help.phaseone.com/en/CO7/Output/File-formats/Colors-in-Capture-One.aspx
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Schewe on March 31, 2014, 10:59:36 pm
Correct, ACR 8.x in Photoshop CC has the new ability to select arbitrary ICC profiles (which is what I'm pretty sure I said on the ACR Forum).
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Lundberg02 on March 31, 2014, 11:41:07 pm
I hope this has been helpful to others, and I thank Andrew, Royce, and Jeff for their information. It will take some effort to establish any benefit from using profiles other than Pro Photo.  I'm not even sure where to start except try using the ProPhoto test file I have. It would be essentially the same as an Ektachrome capture I think.  My present  camera only has 20 bit color depth so I don't think a picture containing deep greens would exercise the process well enough.
I hope the experts will look in again and suggest a file to check this out.
The four choices available to non CC users include the legacy ColorMatch that I don't believe anyone now has a use for. You would think that Adobe would include a newer profile such as PhotoGamut, perhaps, as a standard. Any other suggestions?
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Schewe on April 01, 2014, 12:38:19 am
The four choices available to non CC users include the legacy ColorMatch that I don't believe anyone now has a use for. You would think that Adobe would include a newer profile such as PhotoGamut, perhaps, as a standard. Any other suggestions?

That was then, this is now...ACR 8.x + Photoshop CC allows you to use any ICC profile as the working space. There is zero chance of that change being offered to previous versions of ACR.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: MichaelEzra on April 01, 2014, 12:41:25 am
Rawtherapee (http://rawtherapee.com free, open source, cross-platform) allows to output converted image in a user-selectable ICC profile.
For reference: http://50.87.144.65/~rt/w/index.php?title=Color_Management
See section "Output Profile".
There are additional uniquely supported options available, such as custom gamma for the output encoding.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Lundberg02 on April 01, 2014, 01:09:14 am
I agree that the ability to load any profile makes it moot to include a more modern profile as standard.
I have Rawtherapee, although it's awkward to use in my opinion. It has a lot of fans in the free software community. Thanks for the reference.
There's probably a reference RAW file on the web that has the full gamut of some camera. I'll take a look.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: digitaldog on April 01, 2014, 10:50:04 am
You would think that Adobe would include a newer profile such as PhotoGamut, perhaps, as a standard. Any other suggestions?
Why? The processing color space is ProPhoto RGB primaries, I see as yet, no reason to use anything but that for the master image rendered from that raw converter.

As for ColorMatch RGB, due to the gamma encoding, it's still a valid working space for those targeting to a CMYK halftone process and have to hand of RGB data.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Redcrown on April 01, 2014, 11:58:20 am
I'm confused, would someone explain what this is all about?

What is the benefit of using an arbitrary ICC profile (different than Prophoto) in ACR?

I thought that ACR uses the Melissa/Prophoto colorspace for all internal processing and then converts that result to the profile specified in the Workflow output options. It that not true?

How is that conversion inside ACR different from passing the file to Photoshop as Prophoto and then converting to an arbitrary profile inside Photoshop?
Title: Re: arbitrary RGB profiles for opening RAW
Post by: digitaldog on April 01, 2014, 12:15:56 pm
I thought that ACR uses the Melissa/Prophoto colorspace for all internal processing and then converts that result to the profile specified in the Workflow output options. It that not true?

Melissa RGB is the name of the color space LR/ACR uses for the histogram and RGB values (outside of soft proofing). This is ProPhoto primaries with a sRGB TRC. This is not the color space used for processing! The internal color space has no name, it's using ProPhoto primaries with a 1.0 TRC.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Lundberg02 on April 01, 2014, 02:34:16 pm
I defer to digitaldog for any of the technical considerations of using the existing conversion, but it is my understanding that no matter what you want for rendering, rendering in ACR from its space to ProPhoto, and in Photoshop from ProPhoto to aRGB or sRGB, is relative colorimetric.  This is  caused by the matrix representation of the space being different from the smaller gamut spaces.
This all began because I wanted to find a way to get perceptual, which I am beginning to believe may not be possible.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: digitaldog on April 01, 2014, 02:40:53 pm
This all began because I wanted to find a way to get perceptual, which I am beginning to believe may not be possible.
The profile would have to be a working space V4 profile using the PRMG to do this. Good luck. Further, it's quite possible that a perceptual intent (which varies based on who wrote it) may produce less-good results depending on a large number of factors.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Lundberg02 on April 01, 2014, 02:43:47 pm
One of the members of this forum, jc1, who has not posted for about six months, has a website in which he offers a method of for going from ProPhoto to sRGB using perceptual rendering. He provides an intermediate icc profile for going  from the ProPhoto representation to a "jc1", and then a profile for jc1 to sRGB.  The problem is that you can't download his profiles because his site hasn't been updated since 2011 and the links have expired.  I sent a personal message in this forum but there has been no response. Does anyone know what happened to him?
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Lundberg02 on April 01, 2014, 02:56:26 pm
I came across the PRMG stuff during the course of this quest, and I am aware that there is some major difference between v2 and v4. Andrew has confirmed my suspicions, and I am also aware that there may not be that much difference between perceptual and relative now, but I wanted to see for myself.   Another faint hope dashed by the complexity of color management.  If "Color Management For Photographers" has a discussion of the state of the art of rendering it would be a must have for me.   There are a lot of parts under the hood you can't get to, just like a new car.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: digitaldog on April 01, 2014, 02:59:02 pm
There are several V4 sRGB profiles (some with incorrect white points) out there on the web so converting from ProPhoto RGB to sRGB this way is possible. No 'intermediate" profile necessary. How useful it is would be another question.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Schewe on April 01, 2014, 03:11:14 pm
Andrew has confirmed my suspicions, and I am also aware that there may not be that much difference between perceptual and relative now, but I wanted to see for myself.

You can download V4 ICC profiles for sRGB from the ICC web page (http://www.color.org/srgbprofiles.xalter). Note, the 'sRGB v4 Appearance (beta)' will work in Photoshop while it won't work in Lightroom because it does not have the correct device tag (there is a corrected profile out there). I've found that you can get a different rendering using Perceptual with that profile and it sometimes can improve the rendering of reds/oranges by perceptually mapping the colors that would be out of gamut from sRGB.

Also note that while one can use alternative color spaces in ACR for PS CC, the need to do so is very specific (converting directly from raw to CMYK for example). But in my experience you won't get much in the way of benefit than just doing a profile conversion from PP RGB to some other color space in Photoshop because the main difference between the internal processing color space and an output color space is really only the different tone mapping. the internal space as Andrew says is PP RGB color coordinates with a linear (1.0) gamma while the output is PP RGB and a 1.8 gamma. So, there's no real impact on color, just tone.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Lundberg02 on April 02, 2014, 02:24:27 pm
Well, what I really wanted was ProPhoto perceptually rendered to Adobe 1998, but there isn't  an ICC PRMG for  that I can see anywhere on the ICC site.
I also can't find much on the possible problems with perceptual rendering. I just intuitively don't like the idea that relative can map two out of gamuts to the same in gamut.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Schewe on April 02, 2014, 03:30:37 pm
Actually, it's the receiving profile that controls rendering intent, not the original color space. So, you would need an ARGB V4 ICC profile with perceptual, not a PP RGB V4 profile. But, I've never seen an ARGB V4, only sRGB V4 with perceptual. As far as problems with perceptual, well, that depends entirely on how the perceptual mapping was done. RelCol is standard, Perceptual allows secret sauce for the gamut mapping than may or may not be "optimal".
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Lundberg02 on April 02, 2014, 07:21:52 pm
It looks like the perceptual rending to aRGB could be done with the jc1 intemediate profile, but the download link from his website has expired and he is nowhere to be found. I found a site which showed how to do it in Win PS, but the links to his downloads were also expired.
I have printed from a Pro Photo 16 bit tiff  test target  with Photoshop manages colors to my Epson six color on matte and was pleased with the results. That path was set to perceptual but I suppose it really wasn't.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Schewe on April 02, 2014, 08:07:53 pm
I have printed from a Pro Photo 16 bit tiff  test target directly to my Epson six color on matte and was pleased with the results. That path was set to perceptual but I suppose it really wasn't.

Again, in the ICC profile>profile exchange, the originating profile hands off the profile colors to the interchange color specification (prolly CIE XYZ but could be Lab), the CMM (Color Management Module) takes the CIE XYZ numbers and crunches those numbers into the destination profile color space using a rendering intent. Most matrix based (color spaces) only have a single RelCol rendering, v4 profiles with a perceptual will be able to use perceptual. Output color spaces such as you would find with printer profiles prolly have all 4 of the standard rendering intents; Relative Colorimetric, Perceptual, Saturation and Absolute Colorimetric.

So, if you were transforming from PP RGB to your output profile using a perceptual rendering, you got a perceptual rendering.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Redcrown on April 02, 2014, 11:51:13 pm
Lundberg,

Check your PM here in Lula for help in getting the "jc1" profiles.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Schewe on April 03, 2014, 12:32:06 am
Sorry...got nothing...
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Lundberg02 on April 03, 2014, 01:35:17 am
Redcrown, if you would please also send the jc1 to Jeff Schewe. Possibly they could be made available to all forum members?
 
I sent my Pro Photo test target to my Epson via Photoshop manages colors using the appropriate Epson profile and the correct paper setting in the second Print Settings dialog. The test target I think was the Pro Photo jpg from the Colour Collective.
Not sure a jpg is a fair test, but I have a  tiff somewhere also, and I may have used that.
 So,  Schewe says that printing will produce perceptual  because the printer profile has the requisite matrix, but converting from Pro Photo to aRGB  doesn't. I read that this is due to the PP being matrix and aRGB being 3x3 whatever that is.
This raises the question why the ICC would develop an sRGB perceptual conversion only for web use, since print would achieve it if set that way. But maybe some commercial  printing systems don't have all four intents.

Doesn't Photoshop do everything in L a b ?  Why would they have a setting for Perceptual if it doesn't actually do it from PP to aRGB. You would think that would be explained somewhere in settings. I suppose that aRGB to sRGB actually does Perceptual and the other three.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Schewe on April 03, 2014, 02:30:22 am
Doesn't Photoshop do everything in L a b ?  Why would they have a setting for Perceptual if it doesn't actually do it from PP to aRGB. You would think that would be explained somewhere in settings. I suppose that aRGB to sRGB actually does Perceptual and the other three.

Again, you are failing to understand the fundamental ICC color transforms...(and no, Photoshop switched to CIE XYZ several-many versions ago).

Photoshop (and Adobe in general) has done a disservice to the industry by allowing people to select what are actually, unavailable rendering intents since, well, forever. I don't know why and many of us have complained since, well Photoshop 6, 7 CS, +. To no avail.

And no...ARGB to sRGB won't supply perceptual unless the sRGB has a perceptual rendering intent–which is ONLY available using one of the special sRGB perceptual V4 profiles.

Look bud, you are swimming upstream without a map. You don't know what you don't know. If you want to learn, cool...but what you've "assumed" so far is off base and screwed up.

Go back to the basics...ICC color management starts with an input profile (scanner or camera) which is transformed into a working space (PP RGB, ARGB, sRGB or whatever). You work on the images...if you want to go out to another RGB color space (like the web) you are limited to matrix color space transforms which if you don't have a v4 RGB space (like the V4 sRGB perceptual) means RelCol. If you go to from a "working space" to "output profile" you'll have all 4 of the rendering intents and all 4 will work (to the extent that the profile maker has done their homework).

Look, for the purposes of simplicity, forget about those exotic alternative RGB color spaces. If you are using ACR or LR, use ProPhoto RGB in 16 bit. Once you have that open as your working space, depending on where you want the image to be output to, pick your profile–if you want a perceptual sRGB (for the web), use the sRGB V4 profile. If you are going out to a printer (table based profiles), use the printer profile to soft proof the image and select the best rendering intent for THAT image...

You are making this more complicated that it should be and you lack some basic understanding of what the ICC color management workflow is intended to be.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: digitaldog on April 03, 2014, 09:59:46 am
Look, for the purposes of simplicity, forget about those exotic alternative RGB color spaces.
My thoughts exactly. Color management has enough rabbit holes and problems that we really don't need to manufacturer more complexity when it's not needed.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: madmanchan on April 03, 2014, 12:33:37 pm
One of the applications of choosing an arbitrary output ICC profile in the Workflow Options in ACR is for soft proofing.  For example, you can choose a printer profile and turn on soft proofing (and choice of intent).  I do not recommend opening your document into Ps with such a profile, but while working within ACR itself, some may find this useful.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Lundberg02 on April 03, 2014, 04:07:26 pm
It's BECAUSE I don't understand the process that I bring all this up. Due to your explanation and those of others, I'm getting up to speed. Math doesn't frighten me one bit. If I find something that doesn't make much sense, I ask, and I'm not afraid to expose my ignorance. I have never seen this topic this fully discussed anywhere before, and it's nice to know that experts have complained about the false choices in ACR Workflow Options.
I always use Pro Photo 16 bit as a starting point in RAW, of course. I'm happy that you have confirmed that I get what I ask for in the print process through PS and Epson.  I've learned exactly what you said, that I don't know what I don't know , but I'm not really sure where a person can learn how all the transformations are actually done.  I know I never have seen anywhere that PS uses CIE now instead of L a b.  There's still a lot of stuff out there about doing this or that in L a b, is this still valid?
 I'm going to try Iridient as a result of all this, just for drill.
One (possibly) final question: Does PS CS 5.1 use  a v4 sRGB profile? Adobe never tells you any of these things. The question is academic, because I never convert to sRGB and have no need for it as output.
I think you or digital dog could easily do a full chapter on the real story of rendering in your next book and I wish you would. Maybe Chan has a white paper he could reference, too.  His point about soft proofing is something  not mentioned at all in the Photoshop Forum, which has become so dull I rarely go there.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: digitaldog on April 03, 2014, 04:36:16 pm
Does PS CS 5.1 use  a v4 sRGB profile?

Does it, no. Can it (if one's loaded), I'd suspect so. All the profiles Adobe installes for working space's are V2 matrix profiles. You can only get a Colorimetric intent.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Schewe on April 04, 2014, 12:56:38 am
I know I never have seen anywhere that PS uses CIE now instead of L a b.  There's still a lot of stuff out there about doing this or that in L a b, is this still valid?

If you do a color transform in Photoshop the interchange space for the output profile can be either CIE XYZ or Lab...that's controlled by the output profile (many CMYK profiles seem to use Lab while many RGB printers use CIE XYZ).

I don't recall exactly when Photoshop switched to CIE XYZ as the default interchange color space (pending what a profiles dictates) but I think it's been a long time...well before the "Creative Suite". Could have been Photoshop 6 or 7–I have people who I can ask. I'm pretty sure the change occurred about the time that Thomas Knoll did the Adobe CMM for Photoshop transforms.

In terms of where to go to learn this stuff, well, asking here seems to work and you have two authors here answering your question. Andrew is the author of Color Management for Photographers and my book, The Digital Print goes through the ICC color management workflow. Andrew and I learned this stuff at the feet of Bruce Fraser who is sadly not around to ask but we both have color geek friends we can ask when WE don't know something (although those phone calls always comes at a price :~)

If you want to learn, ask questions...you seem to have learned a lot in this thread so hopefully you won't be flailing about trying to use arbitrary color spaces in ACR (unless you want to upgrade to Photoshop CC).
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Lundberg02 on April 05, 2014, 12:10:43 am
From the Adobe spec for aRGB written 2005:

4.3.8 Encoding and decoding ICC PCS Version 4 values
An image in the ICC Profile Connection Space defined in ICC.1:2004 (Profile version 4.2) using the media-relative colorimetric rendering intent shall be encoded in 24-bit Adobe RGB (1998) color image encoding as specified in this section 4.3.8.
4.3.8.1 Encoding PCS Version 4 in 24-bit Adobe RGB (1998)

Also   http://printing.it-enquirer.com/2006/05/24/icc-color-profile-version-4/     says that all Adobe products are now v4 compliant.

So this should mean that you can do all four renderings from Pro Photo to aRGB. Not sure why sRGB would  not also, except that you're saying no, and the ICC offers a profile to do perceptual.

I agree this forum is a good place to learn. I have your Digital Neg and Digital Print books. In fact , a long time ago you and and others were in a chat room with Dan Margulis, there was some sort of contest and you won his book. You already owned it so you sent it to me. You probably don''t remember , but thanks again.
With Rodney and Chan here also, this is an excellent place to ask questions.
The Photoshop forum is dead, Cambridge in Color is full of nut cases, PhotoLine Forum is only concerned with niceties of the software itself.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Schewe on April 05, 2014, 01:14:45 am
Also   http://printing.it-enquirer.com/2006/05/24/icc-color-profile-version-4/     says that all Adobe products are now v4 compliant.

So this should mean that you can do all four renderings from Pro Photo to aRGB. Not sure why sRGB would  not also, except that you're saying no, and the ICC offers a profile to do perceptual.

Again, V4 "compliant" doesn't mean the profile will have perceptual rendering...and I know for a fact that none of the RGB profiles (matrix based) that ship with Photoshop are V4 profiles with perceptual rendering intents. V4 "allows" perceptual rendering, it doesn't mean there is a perceptual rendering intent...

And yes, I remember you Lundberg, I never forget a pretty face...
Title: Re: arbitrary RGB profiles for opening RAW
Post by: digitaldog on April 05, 2014, 10:34:31 am
So this should mean that you can do all four renderings from Pro Photo to aRGB. Not sure why sRGB would  not also, except that you're saying no, and the ICC offers a profile to do perceptual.

The profile has to be built with the (perceptual) table we're talking about and none are (that are installed by Photoshop) and AFAIK, only a few sRGB profiles were built this way (and as I mentioned, at least one or more is wrong in terms of it's white point).

IF you find a working space profile that has the perceptual rendering intent, you'll know as you'll see it do something different when you pick Perceptual versus RelCol. Now will you like or prefer that rendering? Who know.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Lundberg02 on April 05, 2014, 11:54:47 pm
Shucks, Jeff, I'm blushing, except that it's hard to see because of the egg on my face.
So let's review what we've learned.
You can load arbitrary profiles in Photoshop CC (only). I'm going to ask in the PhotoLine Forum shortly. I know that you can't in ACDSee Pro 3 for Mac, although they said they will add it to their wish list.
In spite of Color Settings, Photoshop only does RelCol unless you load a v4 profile that has the other three.
Printing from ProPhoto files to Epson printers using Photoshop manages colors will offer all the intents.
Iridient may be a good choice for image processing because it offers arbitrary profiles, what about its rendering?.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Schewe on April 06, 2014, 01:01:12 am
In spite of Color Settings, Photoshop only does RelCol unless you load a v4 profile that has the other three.

Correct...in terms of color space (matrix based) profiles.

Printing from ProPhoto files to Epson printers using Photoshop manages colors will offer all the intents.

Correct...most all output profiles (V2 & V4) offer at least 3 out of 4 rendering intents; RelCol, Perceptual & Absolute Colorimetric (Absolute Colorimetric is the same as RelCol except with an absolute rendering of white point–use primarily only for cross rendered proofing) . The 4th, Saturation is little used other than biz graphics.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: digitaldog on April 06, 2014, 10:21:50 am
Iridient may be a good choice for image processing because it offers arbitrary profiles, what about its rendering?.
That's a matter of the profile, not the application. ID will behave like ACR/LR.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: eliedinur on April 06, 2014, 11:27:58 am
Throughout this thread what has mystified me is why nobody has mentioned that since its inception Lightroom has been able to export RGB files in any space, as long as you have the profile in your system's Color folder. Equally mystifying is why a feature that LR has had for 7, 8 years is even today not in PSCS.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: bjanes on April 06, 2014, 12:28:01 pm
Throughout this thread what has mystified me is why nobody has mentioned that since its inception Lightroom has been able to export RGB files in any space, as long as you have the profile in your system's Color folder. Equally mystifying is why a feature that LR has had for 7, 8 years is even today not in PSCS.

I don't understand this post. PS does not have an export function. One can convert to any profile and use save as in any format that you want. Most of us use 16 bit ProPhoto as default, but one can use 8 bit Adobe RGB or Bruce Lindbloom's Beta RGB if file size is a consideration. However, memory and storage are now cheap and 8 bit files don't make much sense except for the web.

Bill
Title: Re: arbitrary RGB profiles for opening RAW
Post by: digitaldog on April 06, 2014, 12:34:47 pm
Throughout this thread what has mystified me is why nobody has mentioned that since its inception Lightroom has been able to export RGB files in any space, as long as you have the profile in your system's Color folder. Equally mystifying is why a feature that LR has had for 7, 8 years is even today not in PSCS.
Since version 5, (1998) Photoshop has had this ability and more. Convert to Profile, Save As command
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Lundberg02 on April 07, 2014, 12:28:17 am
So is someone going to tell me that Soft Proof in Photoshop doesn't render anything but relative?
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Schewe on April 07, 2014, 12:55:41 am
So is someone going to tell me that Soft Proof in Photoshop doesn't render anything but relative?

It will if you use an output profile with a perceptual table in it (most do) but not when using a matrix color space profile–unless it's a V4 profile with a perceptual rendering in it–such as the such as the special sRGB v4 Appearance (beta) (http://www.color.org/srgbprofiles.xalter).
Title: Re: arbitrary RGB profiles for opening RAW
Post by: bjanes on April 07, 2014, 09:08:44 am
It will if you use an output profile with a perceptual table in it (most do) but not when using a matrix color space profile–unless it's a V4 profile with a perceptual rendering in it–such as the such as the special sRGB v4 Appearance (beta) (http://www.color.org/srgbprofiles.xalter).

WE are informed that perceptual rendering is performed via lookup tables in the receiving profile (typically a printer profile with perceptual lookup tables) and this may be the case with V2 profiles. However, with V4 profiles things may be different as I interpret the example in White Paper 26 (http://www.color.org/ICC_White_Paper_26_Using_the_V4_sRGB_ICC_profile.pdf). As explained in the text immediately below Figure 2 in that paper, it states that when the Ver 4 sRGB profile is used as a source, the sRGB colors are re-rendered into the PRM (Perceptual Reference Medium), apparently using the PRM information located in the Ver 4 source profile. When a Ver 4 profile is used as a destination, the colors are re-rendered from the PRM into the destination space. This is a two step process, as compared to one step with Ver 2 profiles.

The link that Jeff provides is an example of using the Ver 4 sRGB profile to print an image rendered into sRGB by a digital camera. This is not how most photographers using raw files would operate. Rather, the source master file would be in ProPhotoRGB and one might wish to use the Ver 4 sRGB profile to re-render into sRGB for use on the web. This is not covered in White Paper 26, but they do cover the case of the original file being in Adobe RGB, where one could convert to sRGB with clipping, assign the Ver 4 sRGB profile and then perform the perceptual rendering.

With a Prophoto source, converting to sRGB could involve quite a lot of clipping and the results might not be pleasing. It would seem better to assign a Ver 4 ProphotoRGB profile (perhaps ISO22028-3_RIMM-RGB-exCR.icc, as mentioned here (http://www.color.org/scene-referred.xalter#profiles)), which would re-render the colors into the PRM and then render into sRGB Ver 4 with the perceptual intent. Does anyone have any experience or comments on this proposed work flow?

Bill









Title: Re: arbitrary RGB profiles for opening RAW
Post by: digitaldog on April 07, 2014, 10:33:30 am
As explained in the text immediately below Figure 2 in that paper, it states that when the Ver 4 sRGB profile is used as a source, the sRGB colors are re-rendered into the PRM (Perceptual Reference Medium), apparently using the PRM information located in the Ver 4 source profile.
Yes, if that V4 profile uses the PRMG of which I know of none that do, at least those built by X-rite, GMB, Copra and DataColor. There may be some profile builder out there that does, I'm not aware of any nor using any such products.

Quote
With a Prophoto source, converting to sRGB could involve quite a lot of clipping and the results might not be pleasing.
That's possible but I've not see it. There is still an issue of a lot of possible OOG colors getting clipped with this process. The gallon of water has to fit into the pint container using either RI, one is supposed to do a 'better/more pleasing' job perceptually but everyone's mileage may vary. It is quite possible a Perceptual RI in this example could make the image less pleasing than a RelCol intent.

Would it be nice if we had the options? Yes. Is it a huge problem? I think not, especially since so few are implementing V4 profiles with the PRMG.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Lundberg02 on April 07, 2014, 03:46:42 pm
This has got me so ticked off that I'm actually going to get off my a** and do some test prints to make sure that my Epson renders. Ticked off because none of this  valuable information has seen the light of day before now to my knowledge, at least not in places accessible to the average person struggling with color management.
One of the authors  posting here could do community service by writing an article ( with copious thanks to me in the introduction) about this hole in the fabric of space-time.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Schewe on April 07, 2014, 03:50:20 pm
This has got me so ticked off that I'm actually going to get off my a** and do some test prints to make sure that my Epson renders. Ticked off because none of this  valuable information has seen the light of day before now to my knowledge, at least not in places accessible to the average person struggling with color management.

I've written about this issue in The Digital Print (http://www.amazon.com/The-Digital-Print-Preparing-Lightroom/dp/0321908457) (and did so well before you asked your questions).
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Lundberg02 on April 07, 2014, 04:38:51 pm
Stout lad! What page?
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Schewe on April 08, 2014, 12:23:09 am
Color Management (Chapter 2) starting on page 40 and a Tip: Matrix Profiles with Perceptual Rendering on page 44.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Lundberg02 on April 08, 2014, 01:38:46 am
Henry Ford once you can have any color car you want as long as it's black.
So I can have any intent I want as long as it's relative. I just printed the ProPhoto Printer test image using Photoshop manages colors in all four intents and there is NO difference between them. This seems to mean that the printer profile does not have anything but relative. Very disappointing.  Color Settings in PS was set to Pro Photo working space, Perceptual intent but this should have no bearing on the print flow.
The only profile I can find on the web that alleges to be perceptual is the ICC Appearance beta for sRGB.
No idea whether Best RGB, PhotoGamut or any others have anything but relative, as it is not mentioned. I feel like I've been swindled. I know of no way to obtain a perceptual rendering intent in my setup. I'll have to try PhotoGamut and  see if has the four intents. You would think it would.  I was unable to to find a PRGM profile in the ICC site oe anywhere else and I had the impression that it has to be built in to an icc profile in order to do its thing.
BTW, Burkhard Huber, developer of PhotoLine, says that you can add arbitrary profiles  to PL using the Camera Profile setting or the document setting.  He claims that all profiles, v2 or v4 will do relative and absolute, but did not offer any solution for perceptual. I doubt his statement about intents.
I read the section of your book, but I don't get a sense of outrage.  Adobe and Epson have failed me, my faith is crumbling like an Obama voter with a new health insurance policy. I'm beginning to doubt gamma  now. Color agnosticism.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Schewe on April 08, 2014, 01:42:26 am
I read the section of your book, but I don't get a sense of outrage.

I don't exhibit "outrage" in a public form, I prefer to express my outrage in private.

And, if you are outputting from PP RGB to an Epson pro printer through all 4 rendering intents and you see no difference, you are doing something wrong (unless your target image falls inside the gamut of the printer). Where did you get the target you printed?
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Lundberg02 on April 08, 2014, 05:12:06 pm
My current printer is an Epson Artisan 725 six color. I know you have at least three Epson pro level printers and I suppose you can confirm that they all do all four renderings. Why would Epson not provide that capability at any price point?
The test image is      PrinterEvaluationImage_V002_ProPhoto.tif       available from several sites on the web such as     
books.outbackphoto.com/DOP2010_03/printer_tests/‎
Title: Re: arbitrary RGB profiles for opening RAW
Post by: digitaldog on April 08, 2014, 05:14:51 pm
My current printer is an Epson Artisan 725 six color. I know you have at least three Epson pro level printers and I suppose you can confirm that they all do all four renderings. Why would Epson not provide that capability at any price point?
The test image is      PrinterEvaluationImage_V002_ProPhoto.tif       available from several sites on the web such as     
books.outbackphoto.com/DOP2010_03/printer_tests/‎
It's the profile we'd need to see. I doubt it doesn't have a perceptual table, I've never seen an output profile that didn't have one.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Schewe on April 08, 2014, 05:54:08 pm
The test image is      PrinterEvaluationImage_V002_ProPhoto.tif       available from several sites on the web such as     
books.outbackphoto.com/DOP2010_03/printer_tests/‎

Hum, I downloaded both the PP RGB and ARGB test file and when I put the ARGB on top of the PP RGB file and set the blend to Difference, I see very, very little difference which leads me to believe that the test file was created in Adobe RGB and then converted to ProPhoto RGB. If each color space was created in a native color space, I would expect the differences to be greater. So, the PP RGB test file is, I think a file that started life as Adobe RGB and was merely converted to ProPhoto RGB. So, that's not a real PP RGB test file.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: samueljohnchia on April 08, 2014, 09:07:00 pm
Hum, I downloaded both the PP RGB and ARGB test file and when I put the ARGB on top of the PP RGB file and set the blend to Difference, I see very, very little difference which leads me to believe that the test file was created in Adobe RGB and then converted to ProPhoto RGB. If each color space was created in a native color space, I would expect the differences to be greater. So, the PP RGB test file is, I think a file that started life as Adobe RGB and was merely converted to ProPhoto RGB. So, that's not a real PP RGB test file.

Not on my end Jeff. I plotted the two test images in ColorThink, against Adobe RGB. The ProPhoto test image does contain colors clearly outside of Adobe RGB.

Edit: Added the difference blend result I got in Photoshop.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Schewe on April 09, 2014, 01:30:58 am
Not on my end Jeff. I plotted the two test images in ColorThink, against Adobe RGB. The ProPhoto test image does contain colors clearly outside of Adobe RGB.

Good to know...I didn't plot the PP RGB against the ARGB image in ColorThink...that seems to be fairly conclusive except I added the ARGB image into the PP RGB image and converted the ARGB to PP RGB as a layer. So, either the original test target was done in PP RGB and transformed to ARGB or the original target was in ARGB and transformed into PP RGB. Only the author of the target would know for sure how the target was made.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: samueljohnchia on April 09, 2014, 02:15:01 am
Only the author of the target would know for sure how the target was made.

I think it's fairly suggestive given that the Adobe RGB version is a jpeg file.  ;)

Based on Outback Photo's webpage description (http://outbackprint.outbackphoto.com/printinginsights/pi048/essay.html), I'll bet that it was indeed a ProPhoto original, and someone dumbed it down to Adobe RGB. The latter cannot be found from the original page.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Lundberg02 on April 09, 2014, 02:48:12 am
Thanks guys, very interesting. I guess I can use the Colorsync utility to inspect the Epson printer profile for the rendering tags, right?
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Schewe on April 09, 2014, 02:52:29 am
Yes...if you look at the various tags...
Title: Re: arbitrary RGB profiles for opening RAW
Post by: bjanes on April 09, 2014, 11:02:18 am
I think it's fairly suggestive given that the Adobe RGB version is a jpeg file.  ;)

Based on Outback Photo's webpage description (http://outbackprint.outbackphoto.com/printinginsights/pi048/essay.html), I'll bet that it was indeed a ProPhoto original, and someone dumbed it down to Adobe RGB. The latter cannot be found from the original page.

That would be my interpretation also. The clipping in the AdobeRGB image is consistent with conversion from a ProPhotoRGB image with a relative colorimetric rendering intent. A test image in AdobeRGB is not suitable for testing with wide gamut inkjet printers as shown below in a Colorthink plot of the AdobeRGB gamut (solid) vs Epson 3880 with glossy Epson paper (wire frame). No knowledgeable photographer would use a test image in AdobeRGB for testing of wide gamut printers.

Bill
Title: Re: arbitrary RGB profiles for opening RAW
Post by: digitaldog on April 09, 2014, 11:22:50 am
Many of those images come from Bill Atkinson who scanned them on his Tango into Lab. I have zero idea what happened after that in respect to these analysis from this one site. I have the original Lab files from Bill so of course it's possible to convert from Lab to whatever you wish.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Schewe on April 09, 2014, 04:01:47 pm
I have the original Lab files from Bill so of course it's possible to convert from Lab to whatever you wish.

Well, if they came from Bill, I have a much higher confidence that Bill did the right thing :~)
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Lundberg02 on April 09, 2014, 04:07:28 pm
is it possible to link to those originals from Atkinson?

I have inspected the Epson profile I used for printing the ProPhoto evaluation image. It contains the B2A0,B2A1, and B2A2 intent tags which I believe are perceptual, relative, and absolute respectively. Now, why did the Photoshop manages colors path fail to honor them?
Title: Re: arbitrary RGB profiles for opening RAW
Post by: samueljohnchia on April 10, 2014, 02:37:42 am
I have inspected the Epson profile I used for printing the ProPhoto evaluation image. It contains the B2A0,B2A1, and B2A2 intent tags which I believe are perceptual, relative, and absolute respectively. Now, why did the Photoshop manages colors path fail to honor them?

Generally speaking, BtoA0, BtoA1, and BtoA2 (or vice versa) are the Perceptual, Colorimetric and Saturation tables respectively. In practice, relative colorimetric and absolute colorimetric rendering intents use the same Colorimetric table, with the latter performing white point mapping while the former does not.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: samueljohnchia on April 10, 2014, 03:21:17 am
Good to know...I didn't plot the PP RGB against the ARGB image in ColorThink...that seems to be fairly conclusive except I added the ARGB image into the PP RGB image and converted the ARGB to PP RGB as a layer. So, either the original test target was done in PP RGB and transformed to ARGB or the original target was in ARGB and transformed into PP RGB. Only the author of the target would know for sure how the target was made.

Jeff, this is really interesting - I've tried doing it by your method (convert), and weirdly, the test image colors expanded when converting from Adobe RGB to ProPhoto. This is reminding me of darlingm's thread (http://www.luminous-landscape.com/forum/index.php?topic=71561.0) a while back.

I've mapped the test image's colors in ColorThink against Adobe RGB (wire frame) and attached it below. The "Adobe RGB" and the "Convert Adobe RGB to ProPhoto RGB" layers are named in the tiff file, layered so one can perform the hide/unhide of layers to view the changes.

So besides the issue that Jeff's method is not accurate for the kind of evaluation he was making, does anyone know why the test image colors will expand when converting from Adobe to ProPhoto? Btw I've also tried converting from sRGB to Adobe RGB with similar colors-are-expanding results.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Lundberg02 on April 10, 2014, 04:33:29 pm
I printed the ProPhoto test target from PhotoLine just for laughs.   I used Printer color and ColorSync, Perceptual, Absolute, and Saturation intents. All were exactly the same and no different from the results from Photoshop
So this is a farce. I can't think of any explanation. I'm going to assume that nothing works as advertised and just go ahead the way most people do, screw around until it looks decent.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: samueljohnchia on April 10, 2014, 07:45:53 pm
I printed the ProPhoto test target from PhotoLine just for laughs.   I used Printer color and ColorSync, Perceptual, Absolute, and Saturation intents. All were exactly the same and no different from the results from Photoshop
So this is a farce. I can't think of any explanation. I'm going to assume that nothing works as advertised and just go ahead the way most people do, screw around until it looks decent.

Something is wrong. When you soft proof in Photoshop, does the preview change as you select differing rendering intents?
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Lundberg02 on April 11, 2014, 12:56:07 am
I'll say something is wrong. But what? There is nothing I can think of that would affect two completely different applications the same way. The only common elements are the image and the printer including its profile.

When you convert back to ProPhoto you're just doing the inverse transform. The color plot should expand. Same with sRGB.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: samueljohnchia on April 11, 2014, 08:00:40 am
When you convert back to ProPhoto you're just doing the inverse transform. The color plot should expand. Same with sRGB.

That was my guess. That's rare that Jeff made an error in this. I initially suspected the difference in the inverse transform (converting back to ProPhoto from Adobe) was due to the difference in white point of the color spaces and the inevitable rounding errors that would occur. However, the sRGB to Adobe RGB convention results in larger differences than the original Adobe RGB colors than I would expect. It is always the bright reds where the differences are the largest.

But what? There is nothing I can think of that would affect two completely different applications the same way. The only common elements are the image and the printer including its profile.

So soft proofing with an epson printer profile does not work except for the relative colorimetric intent?
Well you are on a Mac. Maybe colorsync is screwing up again?
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Lundberg02 on April 11, 2014, 02:55:58 pm
Sorry, I haven't done soft proof as yet. The fact that two different apps do the same thing has me baffled, unless Photoshop uses ColorSync when "Photoshop manages colors". I don't think that's true.  I guess I can soft proof just for drill and then decide about OS and Photoshop preferences.  I may google ColorSync to see if anyone else has had this problem.

Added: Soft proof does nothing either, although I don't trust my sRGB monitor to show it. You would think Saturation would have some effect though.
I was unable to find any trouble reports concerning ColorSync.
I have no idea what to do.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: FranciscoDisilvestro on April 11, 2014, 08:21:17 pm
When you convert back to ProPhoto you're just doing the inverse transform. The color plot should expand. Same with sRGB.

This is not possible. There is no way to know if the color in the smaller gamut came from out of gamut colors in a larger space. Try a different tool.

Regarding perceptual and relative colorimetric rendering intents, I see differences both in softproof and in prints when using a proper output (printer/paper) profile. The diferrences can be very subtle, especially in the prints. I have used the reference image mentioned before and the differences in softproofing are huge (and yes, the file I have is Prophoto RGB). If you don't see any difference, either you profiles are matrix based (Then only relatilve colorimetric) or there is something wrong in you system.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: bjanes on April 11, 2014, 10:07:58 pm
Jeff, this is really interesting - I've tried doing it by your method (convert), and weirdly, the test image colors expanded when converting from Adobe RGB to ProPhoto. This is reminding me of darlingm's thread (http://www.luminous-landscape.com/forum/index.php?topic=71561.0) a while back.

I've mapped the test image's colors in ColorThink against Adobe RGB (wire frame) and attached it below. The "Adobe RGB" and the "Convert Adobe RGB to ProPhoto RGB" layers are named in the tiff file, layered so one can perform the hide/unhide of layers to view the changes.

So besides the issue that Jeff's method is not accurate for the kind of evaluation he was making, does anyone know why the test image colors will expand when converting from Adobe to ProPhoto? Btw I've also tried converting from sRGB to Adobe RGB with similar colors-are-expanding results.

It does not seem reasonable that colors would be expanded when converting from AdobeRGB to ProPhoto, since the purpose of color management is to keep colors the same. To test this phenomenon of expansion, I downloaded Bruce Lindbloom's synthetic color checker (which is in L*a*b). I converted to AdobeRGB in Windows Photoshop CC using the Adobe ACE color engine (the other option is the Microsoft CMM. I don't what options are available on the Mac, but colorsynch is likely an option).

I then converted the AdobeRGB image to ProPhotoRGB (relative colorimetric with dithering off) and used ColorthinkPro to assemble color lists for the two images and calculated Delta Es. A representative range of red values is shown. The RGB values are of course different, since we are using different color spaces, but the L*a*b values are virtually identical with Delta Es of less than one. This test fails to show any expansion. For information on colorlists, I would suggest referring to the Digitaldog's tutorial (http://digitaldog.net/files/ColorGamut.mov).

Bill

Title: Re: arbitrary RGB profiles for opening RAW
Post by: Lundberg02 on April 11, 2014, 10:39:47 pm
I've found some test procedures with profiles to check rendering intents and will try them tomorrow.  I lean toward believing the ProPhoto Printer Evaluation Test Image as being the problem. Hasta mañana.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: samueljohnchia on April 12, 2014, 08:28:47 am
It does not seem reasonable that colors would be expanded when converting from AdobeRGB to ProPhoto, since the purpose of color management is to keep colors the same. To test this phenomenon of expansion, I downloaded Bruce Lindbloom's synthetic color checker (which is in L*a*b). I converted to AdobeRGB in Windows Photoshop CC using the Adobe ACE color engine (the other option is the Microsoft CMM. I don't what options are available on the Mac, but colorsynch is likely an option).

I then converted the AdobeRGB image to ProPhotoRGB (relative colorimetric with dithering off) and used ColorthinkPro to assemble color lists for the two images and calculated Delta Es. A representative range of red values is shown. The RGB values are of course different, since we are using different color spaces, but the L*a*b values are virtually identical with Delta Es of less than one. This test fails to show any expansion. For information on colorlists, I would suggest referring to the Digitaldog's tutorial (http://digitaldog.net/files/ColorGamut.mov).

Bill



Hi Bill, your test using the synthetic colorchecker will not show the "colors expanding" phenomenon, since it does not contain colors outside of Adobe RGB, whether it is generated in Lab or not.

I downloaded another of Bruce Lindbloom's test images, An RGB Image Containing All Possible Colors (http://www.brucelindbloom.com/downloads/RGB16Million.tif.zip). Then I did the following:

1. Assigned ProPhoto RGB to it.
2. Convert that to Adobe RGB.
3. Re-convert that back to ProPhoto RGB.

It exhibits the exact same "colors expanding" phenomenon. I graphed the results in 3D in ColorThink, and also in the Color Worksheet. Unfortunately, the number of unique colors is too large (always more than 60, 000, since the target is made up of gradients) but the pictorial dE map shows a significant number of colors over 4 dE2k.

Please try it yourself.

Lundberg02's explanation by way of inverse transform is not very accurate, I believe, as the difference compared to the original ProPhoto RGB colors is too huge also. I have never tried this experiment before! These are unexpected results, and I hope to know why this behavior is observed.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: samueljohnchia on April 12, 2014, 08:31:26 am
I lean toward believing the ProPhoto Printer Evaluation Test Image as being the problem.

I'm pretty sure that is not the problem - I have no issues with that test image on my end, with different rendering intents, both in soft proofing as well as printed versions.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: bjanes on April 12, 2014, 10:15:34 am
Hi Bill, your test using the synthetic colorchecker will not show the "colors expanding" phenomenon, since it does not contain colors outside of Adobe RGB, whether it is generated in Lab or not.

Yes, I chose that image because it contains no illegal colors.

I downloaded another of Bruce Lindbloom's test images, An RGB Image Containing All Possible Colors (http://www.brucelindbloom.com/downloads/RGB16Million.tif.zip). Then I did the following:

1. Assigned ProPhoto RGB to it.
2. Convert that to Adobe RGB.
3. Re-convert that back to ProPhoto RGB.

It exhibits the exact same "colors expanding" phenomenon. I graphed the results in 3D in ColorThink, and also in the Color Worksheet. Unfortunately, the number of unique colors is too large (always more than 60, 000, since the target is made up of gradients) but the pictorial dE map shows a significant number of colors over 4 dE2k.

Please try it yourself.

Lundberg02's explanation by way of inverse transform is not very accurate, I believe, as the difference compared to the original ProPhoto RGB colors is too huge also. I have never tried this experiment before! These are unexpected results, and I hope to know why this behavior is observed.

According to Lindbloom's site, 12.7% of possible ProPhoto colors are outside of the L*a*b gamut. Assigning ProPhotoRGB to the image with all possible RGB colors would include these illegal colors, and it is not surprising that anomalous results would occur, since L*a*b is used as an intermediate space in the transform.

I'm not certain that there is a real problem here.

Bill
Title: Re: arbitrary RGB profiles for opening RAW
Post by: samueljohnchia on April 12, 2014, 10:56:19 am
Yes, I chose that image because it contains no illegal colors.

According to Lindbloom's site, 12.7% of possible ProPhoto colors are outside of the L*a*b gamut. Assigning ProPhotoRGB to the image with all possible RGB colors would include these illegal colors, and it is not surprising that anomalous results would occur, since L*a*b is used as an intermediate space in the transform.

I'm not certain that there is a real problem here.

Bill


You can also try assigning Adobe RGB (no illegal colors), converting to sRGB, and converting back to Adobe RGB with the same colors-expanding results.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Lundberg02 on April 12, 2014, 04:19:16 pm
http://www.colorwiki.com/wiki/Stunt_Profiles
This link provides output profiles for verifying intents by producing tinted prints. I'll be using this to verify my workflow.
i tried Saturation intent and the print came our blue as specified.
So now it must be the ProPhoto Printer Evaluation Image itself that isn't any different visually in the various intents. How can this be( as my control systems professor used to say after filling his blackboard with an equation and writing an equals sign)?
Title: Re: arbitrary RGB profiles for opening RAW
Post by: bjanes on April 12, 2014, 05:28:59 pm
You can also try assigning Adobe RGB (no illegal colors), converting to sRGB, and converting back to Adobe RGB with the same colors-expanding results.

I performed the test you suggested and got similarly large DeltaEs. This does not make sense to me and there must be some bugs in the workflow. This is a matter for Thomas Knoll or Eric Chan to address. That said, in a color managed workflow all images should be tagged with their color space and there should not be a need for assignment of profiles. One instance where one might not want to embed a profile in one's files is when sending files saved in the native space of a printer or similar output device with a chosen rendering intent. The printer profiles are large and would waste considerable space. The untagged files could be sent directly to the printer without adjustments.

Bill

Title: Re: arbitrary RGB profiles for opening RAW
Post by: samueljohnchia on April 12, 2014, 09:51:59 pm
http://www.colorwiki.com/wiki/Stunt_Profiles
This link provides output profiles for verifying intents by producing tinted prints. I'll be using this to verify my workflow.
i tried Saturation intent and the print came our blue as specified.
So now it must be the ProPhoto Printer Evaluation Image itself that isn't any different visually in the various intents. How can this be( as my control systems professor used to say after filling his blackboard with an equation and writing an equals sign)?

Well, I don't know why either. Either the differences in the ProPhoto Printer Evaluation Image are too subtle for you to pick up (highly unlikely) or something is wrong elsewhere with your system.  ???
Title: Re: arbitrary RGB profiles for opening RAW
Post by: samueljohnchia on April 12, 2014, 09:59:49 pm
I performed the test you suggested and got similarly large DeltaEs. This does not make sense to me and there must be some bugs in the workflow. This is a matter for Thomas Knoll or Eric Chan to address. That said, in a color managed workflow all images should be tagged with their color space and there should not be a need for assignment of profiles. One instance where one might not want to embed a profile in one's files is when sending files saved in the native space of a printer or similar output device with a chosen rendering intent. The printer profiles are large and would waste considerable space. The untagged files could be sent directly to the printer without adjustments.

Bill



Thanks for the confirmation of this phenomenon!

So this behavior definitely should be treated as a bug, not something normal in the way profiles are converted? It would seem almost impossible that this issue was not brought up before.

I beg to differ, profiles are assigned all the time, whether we are involved or not. Raw converters assign profiles to raw images. In a color managed workflow, one also must assign a scanner profile to a film scan, and then usually convert it to one of the many well behaved RGB working spaces for further editing. So what happens when one assigns a scanner profile (smaller gamut) and converts to ProPhoto RGB (wider gamut)? Are colors going to expand as well?
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Lundberg02 on April 13, 2014, 12:37:25 am
Well, I don't know why either. Either the differences in the ProPhoto Printer Evaluation Image are too subtle for you to pick up (highly unlikely) or something is wrong elsewhere with your system.  ???
I have looked at the various prints under supposedly full spectrum lighting and can't see any difference. Can you tell me your visual impression of the Saturation intent print? this should be the one with the most noticeable change I would think. If you could point out which part of the image to examine I would appreciate it. Maybe post a crop of side by side with relative.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: samueljohnchia on April 13, 2014, 04:45:54 am
I have looked at the various prints under supposed;y flu spectrum lighting and can't see any difference. Can you tell me your visual impression of the Saturation intent print? this should be the one with the most noticeable change I would think. If you could point out which part of the image to examine I would appreciate it. Maybe post a crop of side by side with relative.

Here you go. It's a crop of the color gradients and color patches from the Outback modified test image, tiff format, with screenshots as layers. The background layer is relative colorimetric (no bpc), and perceptual and saturation are labelled accordingly. I converted using a custom profile I made with i1Profiler, which is what the newer Epson profiles are made with too.

As expected, Perceptual maintains better separation along the gamut boundary, and relative colorimetric appears to clip colors outside the printer's gamut. Saturation boosts the saturation of colors significantly.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Hening Bettermann on April 13, 2014, 05:18:51 pm
Samueljohnchia,
I see only 1 image with no labels - ?
Title: Re: arbitrary RGB profiles for opening RAW
Post by: samueljohnchia on April 13, 2014, 07:38:59 pm
Samueljohnchia,
I see only 1 image with no labels - ?

You have to download it and open it in Photoshop. It's a tiff file with layers. The layers are labelled accordingly.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Hening Bettermann on April 14, 2014, 06:18:36 am
Ooops! Thank you.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Lundberg02 on April 14, 2014, 04:16:48 pm
i certainly thank you for the effort involved in making that image. I was able to see a noticeable shift in saturation between the perceptual layer and the saturation layer, but only in the second horizontal bar in the magenta. Without using a spectrometer, I don't see any differences in that same bar in my prints from Photoshop and Photoline.
Your image on my sRGB monitor is more saturated than my prints to begin with.
I  don't think I know what is up with all this.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: samueljohnchia on April 14, 2014, 07:50:15 pm
i certainly thank you for the effort involved in making that image. I was able to see a noticeable shift in saturation between the perceptual layer and the saturation layer, but only in the second horizontal bar in the magenta. Without using a spectrometer, I don't see any differences in that same bar in my prints from Photoshop and Photoline.

If the only difference you see in my tiff on your sRGB (I'm assuming it's full sRGB coverage) display is in just the magenta patches, I can't help you. I have looked at it on my lowly laptop display which has only about 70% sRGB coverage, and I can see differences almost everywhere, but it's just a lot harder to see them in the lighter, less colorful patches. Have you taken the X-rite color test (http://www.xrite.com/online-color-test-challenge) before? What is your score?

Quote
Your image on my sRGB monitor is more saturated than my prints to begin with.

Well, its a crop of Outbackphoto's ProPhoto RGB printer test image, not mine, rendered into one of my custom printer profiles.  ;) The lighter and less colorful patches as well as the near-white and near-black parts of the gradients are definitely possible colors in many real world color images, and may be more useful for your judgement.

Quote
I  don't think I know what is up with all this.

Certainly if your images comprise a tiny gamut, well within sRGB, then the differences between rendering intents will be small and difficult to see in side-by-side prints or side by side on a display. The flash-to-compare trick with layered renderings or using the preview function in Photoshop's soft proofing makes it a great deal easier to catch subtle differences. Then look out for those differences in your prints. It's a great way to train your eyes.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Lundberg02 on April 15, 2014, 01:56:45 am
I have that color test, but haven't used it yet. My printer's gamut is larger than sRGB according to ColorSync  Utility, it's a six color.  I'm going to check all settings in Photoshop and PhotoLine again, but I have a stack of eight prints that all look  identical to me. They were all printed to bright copy paper to save money, using the appropriate Epson settings.  The paper could be part of the problem, I suppose, but the fact that Saturation shows no effect is almost impossible to believe.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Lundberg02 on April 15, 2014, 06:41:51 pm
I checked all settings and printed the ProPhoto printer eval again in Saturation and Perceptual on Epson Presentation Matte. Can see no difference.  I think I'm being color managed by an invisible geek who has decided to give me the same output no matter what I input. I downloaded an aRGB target that I will try the intents on later today.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: digitaldog on April 15, 2014, 06:43:43 pm
I checked all settings and printed the ProPhoto printer eval again in Saturation and Perceptual on Epson Presentation Matte. Can see no difference. 
Next stop: http://www.xrite.com/online-color-test-challenge
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Lundberg02 on April 17, 2014, 11:47:16 pm
I'll be taking the test, but I really can't see how it applies to looking at eight prints that aren't different, and particularly because I can see differences in the layers that samueljohnchia created without a problem
By the way, Andrew, your digitaldog page doesn't display properly in Safari. I've looked at in every version of Safari from 3 to 7 and the text overlaps itself all over the page. I have never been able to download your aRGB image because the link is covered up by other text.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: digitaldog on April 18, 2014, 10:50:11 am
I'll be taking the test, but I really can't see how it applies to looking at eight prints that aren't different, and particularly because I can see differences in the layers that samueljohnchia created without a problem
Well doesn't samueljohnchia see the differences? If so, maybe you're color blind. That's about the only explanation I can come up with for your inability to see the differences the rest of us see all the time on all manner of images we work with.
Quote
By the way, Andrew, your digitaldog page doesn't display properly in Safari. I've looked at in every version of Safari from 3 to 7 and the text overlaps itself all over the page. I have never been able to download your aRGB image because the link is covered up by other text.
It's fine on this end just as the issues you raise in 5 pages here seem only to affect you. We're getting nowhere,time to move on.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Lundberg02 on April 18, 2014, 05:33:41 pm
It's actually the tips and tricks page of your site, sorry. It does the same thing in Firefox. The line spacing is not rendered correctly and text is laid on top of one another. I am not color blind, attested to by several eminent organizations including the US Navy and Air Force.  I do see the differences samuel posted as layers, and in other sites on the web.  I am going to get to the bottom of this eventually.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: digitaldog on April 18, 2014, 05:40:15 pm
It's actually the tips and tricks page of your site, sorry. It does the same thing in Firefox. The line spacing is not rendered correctly and text is laid on top of one another.
Again, this is some issue only you have reported in the years and years that page has been up. No issue on this end! Proof:
(http://www.digitaldog.net/files/Tips.jpg)
Some of us ARE trying to help you but short of paying you a visit (for pay), there isn't much more I can do to help you either with the web page which appears just fine or with the differences in seeing the rendering intent upon images. Sorry.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Lundberg02 on April 18, 2014, 07:15:45 pm
Well, I was sure your end would look ok. So, no one else has ever reported that the text was overprinted. Weird.
I can now report that the PDI target downloaded from g ballad's page, aRGB jpg, definitely shows differences in all four renderings on copy paper with the appropriate settings in Photoshop manages color.  Going back to my ProPhoto prints from Photoshop  and knowing what to look for, I can see the same slight difference in the faces.
I've learned quite a bit from this exercise, and I hope I haven't wasted a lot of anyone's time. Thank you all.
Don't hate me for being popular, it's such a grind.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: digitaldog on April 18, 2014, 07:17:23 pm
Well, I was sure your end would look ok. So, no one else has ever reported that the text was overprinted.

Correct!
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Bryan Conner on April 19, 2014, 12:24:53 am
The tips and tricks page on Andrew's site works perfectly for me in both Firefox and Google Chrome.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Lundberg02 on April 19, 2014, 01:41:53 am
I guess I'm in for another endless browser malfunction google .
Sidenote: I have tried Iridient and it was ghastly, so I hope to send the developer a screenshot of how it opened my RAW. He was very prompt replying when I asked about the original subject of this thread, so I hope he can explain what is happening to my file from a camera that it is supposed to support and does in fact appear in their list of input. It came out as an overexposed magenta only image. Pretty disconcerting, since ACR and several other apps handle it nicely.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Lundberg02 on April 20, 2014, 02:18:35 am
rather than search endlessly, I went into Sfari Preferences and changed the encoding to Western Roman Mac and the minimim font to 14 point. That almost cured the text overlap. I'll do much the same in Firefox. I was able to download the aRGB tif at last.
Title: Re: arbitrary RGB profiles for opening RAW
Post by: Lundberg02 on April 24, 2014, 01:19:39 am
I case anyone is still reading this thread, I had a problem with a RAW file in Iridient Developer 2.3.4. The developer confirmed it and is releasing 2.3.5 late this week.
This is a public service announcement and I approved this message.