Does anyone know of a Photoshop plugin that can display TAC warnings as you are working on an image. I'm not talking about the Info palette or a specific Action for Photoshop. I want to be warned that I am going over the TAC limits set by the Output ICC Profile I am using as I am manipulating the image. Something similar to the Gamut warning maybe. Thanks - Mike Stewart
On 11 Dec 2014, at 20:12, Mike Stewart <mstewart@embassygraphics.com> wrote:
Does anyone know of a Photoshop plugin that can display TAC warnings as you are working on an image. I'm not talking about the Info palette or a specific Action for Photoshop. I want to be warned that I am going over the TAC limits set by the Output ICC Profile I am using as I am manipulating the image. Something similar to the Gamut warning maybe.
Don’t see why users should need to get a plugin? Photoshop’s Gamut Warning *should* show this! Why doesn’t it? -- Martin Orpen Idea Digital Imaging Ltd
Martin, This kind of plug-in would be very useful, akin to the Print Preview dialog in Acrobat where the TIL can be observed on a CMYK image. I, too, would be very interested in such a plug-in (is that too hard to do for Adobe?). Mind you, one can never go over the TIL built inside a CMYK output profile for as long as the image is in RGB space, only at the time of conversion does the R=G=B=0 gets mapped to whatever 300% or 320% or whatever TIL embodied in an output profile. This has nothing to do with gamut warning, Martin. In my humble knowledge. Best / Roger -----Original Message----- From: colorsync-users-bounces+graxx=videotron.ca@lists.apple.com [mailto:colorsync-users-bounces+graxx=videotron.ca@lists.apple.com] On Behalf Of Martin Orpen Sent: 11 décembre 2014 18:21 To: 'colorsync-users?lists.apple.com' List Subject: Re: Images and TAC values On 11 Dec 2014, at 20:12, Mike Stewart <mstewart@embassygraphics.com> wrote:
Does anyone know of a Photoshop plugin that can display TAC warnings as you are working on an image. I'm not talking about the Info palette or a specific Action for Photoshop. I want to be warned that I am going over the TAC limits set by the Output ICC Profile I am using as I am manipulating the image. Something similar to the Gamut warning maybe.
Don’t see why users should need to get a plugin? Photoshop’s Gamut Warning *should* show this! Why doesn’t it? -- Martin Orpen Idea Digital Imaging Ltd _______________________________________________ Do not post admin requests to the list. They will be ignored. Colorsync-users mailing list (Colorsync-users@lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/colorsync-users/graxx%40videotron.ca This email sent to graxx@videotron.ca
On 11 Dec 2014, at 23:36, Roger Breton <graxx@videotron.ca> wrote:
Mind you, one can never go over the TIL built inside a CMYK output profile for as long as the image is in RGB space, only at the time of conversion does the R=G=B=0 gets mapped to whatever 300% or 320% or whatever TIL embodied in an output profile.
Which is why it seemed clear that the OP was talking about editing CMYK images…
This has nothing to do with gamut warning, Martin. In my humble knowledge.
Really? If you edit a CMYK image which has a TAC of 300% and make it 400% Photoshop’s Gamut Warning should show this shouldn’t it? If you set the soft proof profile to something similar — for example the BasICColor version of ISO Coated v2 (300) while your image is in the usual ICC version it will “kind of” do it. 310% TAC is outside of the limits of the profile. Why doesn’t Photoshop’s gamut warning show this? -- Martin Orpen Idea Digital Imaging Ltd
Martin/Roger/Mike, I believe Roger is correct but he needed to elaborate. I stick my neck out and try. The Total Area Coverage (used to be Total Ink Weight) is the sum of the highest dot percentages in each channel of a CMYK file. These are necessarily customised for a particular printing condition for a host of reasons related to the specific transfer characteristics that result from the combination of ink, substrate, press and printing process. For example, newsprint will support a much lower TAC than sheet-fed coated as it is more absorbent and uses inks with lower tack and viscosity to cope with the run speeds. Laying down 'runnier' inks on 'blotting paper' generates far greater dot gain, or TVI, and is therefore harder to control in the shadows which soon 'plug up' if an inappropriate coated sheet-fed profile was used. Just to complicate the dynamic it is possible to generate and use multiple profiles, with the same TAC, for the same printing condition to produce the same colour space, or gamut. This is one reason why standards-based profiles are continually 'refined' - to achieve a more optimum operation for a given printing condition and its colour space. Using the wrong profile, with a higher TAC, would result in no greater gamut but it would certainly result in more poorly rendered detail, especially in the midtone to shadow region. This means that the Gamut View in Photoshop, which must be comparing Lab coordinates as it describes appearance, is telling you that the colours are out of gamut or beyond the limits of the colour space for a specified printing condition and profile. It does not tell you if that profile is appropriate for the specified printing condition and will not care what the TAC is. It is only concerned with the appearance of the colour. Mark On Fri, Dec 12, 2014 at 11:04 AM, Martin Orpen <martin@idea-digital.com> wrote:
On 11 Dec 2014, at 23:36, Roger Breton <graxx@videotron.ca> wrote:
Mind you, one can never go over the TIL built inside a CMYK output
profile for as long as the image is in RGB space, only at the time of conversion does the R=G=B=0 gets mapped to whatever 300% or 320% or whatever TIL embodied in an output profile.
Which is why it seemed clear that the OP was talking about editing CMYK images…
This has nothing to do with gamut warning, Martin. In my humble knowledge.
Really?
If you edit a CMYK image which has a TAC of 300% and make it 400% Photoshop’s Gamut Warning should show this shouldn’t it?
If you set the soft proof profile to something similar — for example the BasICColor version of ISO Coated v2 (300) while your image is in the usual ICC version it will “kind of” do it.
310% TAC is outside of the limits of the profile. Why doesn’t Photoshop’s gamut warning show this?
-- Martin Orpen Idea Digital Imaging Ltd _______________________________________________ Do not post admin requests to the list. They will be ignored. Colorsync-users mailing list (Colorsync-users@lists.apple.com) Help/Unsubscribe/Update your Subscription:
https://lists.apple.com/mailman/options/colorsync-users/mark.stegman%40gmail...
This email sent to mark.stegman@gmail.com
On 12 Dec 2014, at 00:20, Mark Stegman <mark.stegman@gmail.com> wrote:
This means that the Gamut View in Photoshop, which must be comparing Lab coordinates as it describes appearance, is telling you that the colours are out of gamut or beyond the limits of the colour space for a specified printing condition and profile. It does not tell you if that profile is appropriate for the specified printing condition and will not care what the TAC is. It is only concerned with the appearance of the colour.
But this would be trivial for Adobe… Almost as trivial as them making the Desaturate command (shift-command-U) work in CMYK — so I won’t hold my breath :-) If I feed CMYK values into ISO Coated v2 (300) I can get Lab values back. At 300% TAC the L values are around 9.8. At 400% TAC you get L values of 8.7 — which aren’t achievable, but they are still returned by the profile. Why can’t anything lower than the L value at the TAC limit be given a gamut warning? -- Martin Orpen Idea Digital Imaging Ltd
Martin, I'm not sure what you mean by "trivial". I guess what I am saying is that you could, in theory, create a profile with 400% TAC and still be within gamut for a specific printing condition however, protocol prevents me from saying how it would turn out on any conventional printing process. I would like to emphasise that TAC should be specified during profile creation. By simply changing it in the image with the ISO Coated v2 profile I would say that you are, in effect, editing the profile which will no longer be a valid representation of the printing condition. This is only going to produce Lab values which are 'extrapolated' from the profile. It doesn't tell you anything about the reality of final printed product and its appearance. As for gamut view, I would like to qualify what I have said already. If you have a profile assigned that is a valid representation of the printing condition you are targeting, whatever the TAC may be, gamut view should give you a fairly accurate preview of the end result ( even though there are still problems with the rendering of shadows on screen as you have already noted in another discussion). You still have to remember that TAC is all about shadows where the maximum values for each channel is present. In other words, 4-colour blacks. Having Black Point Compensation applied is probably more important for rendering shadows correctly ( depending on the Rendering Intent). TAC doesn't tell you much about clean saturated colours and everything else in between which is where differences in gamut are most apparent. Mark
On 12 Dec 2014, at 11:40 am, Martin Orpen <martin@idea-digital.com> wrote:
On 12 Dec 2014, at 00:20, Mark Stegman <mark.stegman@gmail.com> wrote:
This means that the Gamut View in Photoshop, which must be comparing Lab coordinates as it describes appearance, is telling you that the colours are out of gamut or beyond the limits of the colour space for a specified printing condition and profile. It does not tell you if that profile is appropriate for the specified printing condition and will not care what the TAC is. It is only concerned with the appearance of the colour.
But this would be trivial for Adobe…
Almost as trivial as them making the Desaturate command (shift-command-U) work in CMYK — so I won’t hold my breath :-)
If I feed CMYK values into ISO Coated v2 (300) I can get Lab values back.
At 300% TAC the L values are around 9.8.
At 400% TAC you get L values of 8.7 — which aren’t achievable, but they are still returned by the profile.
Why can’t anything lower than the L value at the TAC limit be given a gamut warning?
-- Martin Orpen Idea Digital Imaging Ltd _______________________________________________ Do not post admin requests to the list. They will be ignored. Colorsync-users mailing list (Colorsync-users@lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/colorsync-users/mark.stegman%40gmail...
This email sent to mark.stegman@gmail.com
On 12 Dec 2014, at 02:36, Mark Stegman <mark.stegman@gmail.com> wrote:
I'm not sure what you mean by "trivial"
Let me make it clearer for you then… Having Photoshop’s Gamut Warning indicate when a CMYK image has exceeded the profile’s ink limit would be very useful. This feature is in Acrobat so I doubt that it’s a biggie for one of Adobe’s talented people to add it to Photoshop. This would hopefully lead to fewer people dropping crap CMYK images which exceed ink limits into pre-press workflows and allow operators who need to edit images in Photoshop to quickly ascertain if there are TAC problems without having to waste time roaming over the images with one eye on the info window. -- Martin Orpen Idea Digital Imaging Ltd
I’m not understanding at all how exceeding the TAC is an “out-of-gamut” issue. It’s not OoG, it’s more of a print quality issue. In the case of certain digital presses, maximum density or min L* is reached at 100% TAC (100% black only)……it would be a good trick to have a plug-in report that a 200% secondary overprint is NOT exceeding TAC while any amount of CMY added to 100K would exceed the TAC. :-) Terry
On Dec 12, 2014, at 5:33 AM, Martin Orpen <martin@idea-digital.com> wrote:
On 12 Dec 2014, at 02:36, Mark Stegman <mark.stegman@gmail.com> wrote:
I'm not sure what you mean by "trivial"
Let me make it clearer for you then…
Having Photoshop’s Gamut Warning indicate when a CMYK image has exceeded the profile’s ink limit would be very useful.
This feature is in Acrobat so I doubt that it’s a biggie for one of Adobe’s talented people to add it to Photoshop.
This would hopefully lead to fewer people dropping crap CMYK images which exceed ink limits into pre-press workflows and allow operators who need to edit images in Photoshop to quickly ascertain if there are TAC problems without having to waste time roaming over the images with one eye on the info window.
-- Martin Orpen Idea Digital Imaging Ltd _______________________________________________ Do not post admin requests to the list. They will be ignored. Colorsync-users mailing list (Colorsync-users@lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/colorsync-users/wyseconsul%40mac.com
This email sent to wyseconsul@mac.com
On 12 Dec 2014, at 17:03, Terence Wyse <wyseconsul@mac.com> wrote:
I’m not understanding at all how exceeding the TAC is an “out-of-gamut” issue. It’s not OoG, it’s more of a print quality issue.
It is a gamut issue in CMYK profiles — how can you fail to understand that? And even if you can’t, where would you put a TAC warning in Photoshop if not in the View menu? -- Martin Orpen Idea Digital Imaging Ltd
On Dec 12, 2014, at 9:44 AM, Martin Orpen <martin@idea-digital.com> wrote:
On 12 Dec 2014, at 17:03, Terence Wyse <wyseconsul@mac.com> wrote:
I’m not understanding at all how exceeding the TAC is an “out-of-gamut” issue. It’s not OoG, it’s more of a print quality issue.
It is a gamut issue in CMYK profiles — how can you fail to understand that?
I think that Terry is suggesting that potentially all CMYK combinations could be considered in gamut (generically) but that TAC sets a separate limit of advisable combinations. By generically I mean that there are certainly CMYK printing systems that will happily accept inking levels up to 400% without any issues so Photoshop needs to take those into consideration as well. While you may consider a TAC level part of the gamut boundary, I don’t think that I would. Or at least, I would not consider it part of the device gamut boundary. It could be argued that it should be considered part of the profile’s rendered gamut boundary.
And even if you can’t, where would you put a TAC warning in Photoshop if not in the View menu?
That’s a logical place for it, I think. regards, Steve
On 12 Dec 2014, at 23:08, Steve Upton <upton@chromix.com> wrote:
By generically I mean that there are certainly CMYK printing systems that will happily accept inking levels up to 400% without any issues so Photoshop needs to take those into consideration as well. While you may consider a TAC level part of the gamut boundary, I don’t think that I would. Or at least, I would not consider it part of the device gamut boundary. It could be argued that it should be considered part of the profile’s rendered gamut boundary.
As an image maker, that’s precisely what I’m arguing. I’d consider any CMYK values that can’t be “round-tripped” back through a CMYK profile to form a gamut boundary which will clearly highlight TAC issues. -- Martin Orpen Idea Digital Imaging Ltd
The Gamut warning isn’t going to help, for one, it’s quite buggy. It’s possible for it to show you OOG color overlay when you apply the same profile as the image itself! That’s wrong. The expressed needs are in line but Photoshop’s gamut warning, which predates ICC color management introduced in Photoshop 5 (1998) isn’t the tool to look at. The same OOG bug shows up in the ACR engine. What we need from Adobe is a range of OOG’s that are not broken, kind of like what we see in ColorThink Pro. If they could work in TAC too, so much the better. Andrew Rodney http://www.digitaldog.net/
On Dec 12, 2014, at 7:50 AM, Andrew Rodney <andrew@digitaldog.net> wrote:
The Gamut warning isn’t going to help, for one, it’s quite buggy.
Seems to me that this is something that shouldn't be all that much of a challenge, and that you could probably create an action that would run quickly that would do the job. Basically, convert the image to the destination profile and then select all pixels with a value of either 255 or 0 in any one of the channels. An action is obviously much less than ideal; too slow and clunky. But if I'm right and it would be easy to create such an action, it should be equally easy to code it into the application itself. b&
This is an interesting conversation. First, I want to salute Martin's original suggestion to do a Profile to Profile conversion or Proofing Setup in order to trigger a Gamut Warning. I ought to try this trick but, I suspect it won't be of much help for me :( Second, I agree this new "Viewing option" should be located under the View menu. That's a no brainer. Third, I often run in exceeding the prescribed TIL when editing images myself. So I can vouch to the usefulness of such a viewing option in Photoshop. I remember, once, using the Curves tool, to satisfy the craving for a client for contrast; by pulling the black point in from the right, on a CMYK image, all of a sudden, the darkest tones of the image, that were already well mapped to a max of 300%, became 310%, 320%, 340% and so on. And I did not pay attention to the fact that the extra contrast I was witnessing was achieved at the expense of overstepping the 300% boundary. By the time I realize my "oversight" it was too late. Needless to say I didn't do the same mistake twice but suffice to say that, had I had access to a "TIL Preview" somewhere, in Photoshop, a mode I could have turned on, à la Gamut Warning, I would have seen the mistake I was making. This could have taken the form of red pixels overlaid on the image, indicating an excess of a selected maximum TIL. Then, having been "warned" that way by Photoshop, it would have been a matter of deciding which pixels to push closer to the 300% boundary. No offense, Martin, but in this case, I tend to think that, a P2P proofing setup is a "poor man" TIL Preview. And I fail to see this as a feature that could be tied to ICC workflow? I tend to see it as a straightforward, mechanical kind of "Device CMYK" dumb interface. Flip it on, flip in off. You need it? You activate it. You don't? You hide it. No mess, no fuss. Instant gratification. To me, it has nothing to do with Gamut Warning. But, again, no offense and I'll gladly give your trick a try until Adobe comes up with an update with that viewing option, in a future update. Best / Roger -----Original Message----- From: colorsync-users-bounces+graxx=videotron.ca@lists.apple.com [mailto:colorsync-users-bounces+graxx=videotron.ca@lists.apple.com] On Behalf Of Ben Goren Sent: 12 décembre 2014 10:11 To: ColorSync List Subject: Re: Images and TAC values On Dec 12, 2014, at 7:50 AM, Andrew Rodney <andrew@digitaldog.net> wrote:
The Gamut warning isn’t going to help, for one, it’s quite buggy.
Seems to me that this is something that shouldn't be all that much of a challenge, and that you could probably create an action that would run quickly that would do the job. Basically, convert the image to the destination profile and then select all pixels with a value of either 255 or 0 in any one of the channels. An action is obviously much less than ideal; too slow and clunky. But if I'm right and it would be easy to create such an action, it should be equally easy to code it into the application itself. b& _______________________________________________ Do not post admin requests to the list. They will be ignored. Colorsync-users mailing list (Colorsync-users@lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/colorsync-users/graxx%40videotron.ca This email sent to graxx@videotron.ca
Roger, On Sat, Dec 13, 2014 at 1:12 PM, Roger Breton <graxx@videotron.ca> wrote:
This is an interesting conversation.
First, I want to salute Martin's original suggestion to do a Profile to Profile conversion or Proofing Setup in order to trigger a Gamut Warning. I ought to try this trick but, I suspect it won't be of much help for me :(
I missed that however, as you originally said, I don't think Gamut View addresses the problem of alerting you to exceeding TIL/TAC. As Terry points out exceeding TAC this will have little effect on the gamut. TAC is about the maximum ink limit for a specific printing process - the darkest shadows where there is little or no colour. It will result in less detail and other associated problems that result from trying to put more ink on the paper than the printing process can tolerate. As any printer will know putting more ink on the paper doesn't necessarily lead to more colour, darker shadows and or higher densities. The advantage of Gamut View is in displaying those COLOURS that will be clipped when converting to another colour space. Second, I agree this new "Viewing option" should be located under the View
menu. That's a no brainer.
Agreed.
Third, I often run in exceeding the prescribed TIL when editing images myself. So I can vouch to the usefulness of such a viewing option in Photoshop. I remember, once, using the Curves tool, to satisfy the craving for a client for contrast; by pulling the black point in from the right, on a CMYK image, all of a sudden, the darkest tones of the image, that were already well mapped to a max of 300%, became 310%, 320%, 340% and so on. And I did not pay attention to the fact that the extra contrast I was witnessing was achieved at the expense of overstepping the 300% boundary. By the time I realize my "oversight" it was too late. Needless to say I didn't do the same mistake twice but suffice to say that, had I had access to a "TIL Preview" somewhere, in Photoshop, a mode I could have turned on, à la Gamut Warning, I would have seen the mistake I was making. This could have taken the form of red pixels overlaid on the image, indicating an excess of a selected maximum TIL. Then, having been "warned" that way by Photoshop, it would have been a matter of deciding which pixels to push closer to the 300% boundary.
I believe this is a trap of working in CMYK. If you had been making your adjustment in RGB and previewing them using the Proof Setup you would have seen the result of the targeted conversion and known what to expect in terms of gamut mapping. As Andrew has pointed on this forum numerous times Gamut View is very limited in what it can show you just by the fact that it covers everything that is OoG with a flat grey daub. It doesn't distinguish OoG colours by the amount they go beyond the the limits of the printing condition. For this reason Proof Setup is preferable but it only to alert you to how mostly saturated colours will be affected. What you need to explain to your client is that, while they may not like the result of the conversion there is little that you can do about it other than using an entirely different printing process. The resultant conversion will apply the appropriate values for the targeted printing condition, including TAC/TIL. How you optimise each image for that conversion is another story... and a very subjective one at that.
No offense, Martin, but in this case, I tend to think that, a P2P proofing setup is a "poor man" TIL Preview. And I fail to see this as a feature that could be tied to ICC workflow? I tend to see it as a straightforward, mechanical kind of "Device CMYK" dumb interface. Flip it on, flip in off. You need it? You activate it. You don't? You hide it. No mess, no fuss. Instant gratification. To me, it has nothing to do with Gamut Warning. But, again, no offense and I'll gladly give your trick a try until Adobe comes up with an update with that viewing option, in a future update.
Me too. Mark
On 13 Dec 2014, at 02:12, Roger Breton <graxx@videotron.ca> wrote:
No offense, Martin, but in this case, I tend to think that, a P2P proofing setup is a "poor man" TIL Preview. And I fail to see this as a feature that could be tied to ICC workflow? I tend to see it as a straightforward, mechanical kind of "Device CMYK" dumb interface. Flip it on, flip in off. You need it? You activate it. You don't? You hide it. No mess, no fuss. Instant gratification. To me, it has nothing to do with Gamut Warning. But, again, no offense and I'll gladly give your trick a try until Adobe comes up with an update with that viewing option, in a future update.
Roger It’s not a “trick” that I use — just an observation… I don’t use it. I don’t see it as workable. I also don’t see it as part of any conversion workflow, largely because we don’t even use Photoshop for CMYK conversions! I really don’t see why this should be any kind of controversial issue? Lots of people want this feature in Photoshop. This feature is already available in both Acrobat AND IN INDESIGN FFS! so why are Photoshop users left in the stupid position of having to place an image in InDesign just to get a “gamut warning style” TIL preview! -- Martin Orpen Idea Digital Imaging Ltd
The OP expressed a desire for a plugin or some kind of live warning system but not "a specific Action for Photoshop". I agree with Mike and Martin that such a thing would be useful. FWIW, there is a set of actions out there that I use all the time: http://www.curvemeister.com/downloads/cmyk_tac/index.htm Indeed, these are "clunky", but not as clunky as placing the image in InDesign or saving as a PDF to open in Acrobat. It is kind of weird that this isn't available in Photoshop. Maybe if everyone on the colorsync list piled onto this feature request Adobe would notice: http://feedback.photoshop.com/photoshop_family/topics/cmyk_ink_density_gamut... -Todd Shirley
Lots of people want this feature in Photoshop.
This feature is already available in both Acrobat AND IN INDESIGN FFS! so why are Photoshop users left in the stupid position of having to place an image in InDesign just to get a “gamut warning style” TIL preview!
-- Martin Orpen
participants (9)
-
Andrew Rodney
-
Ben Goren
-
Mark Stegman
-
Martin Orpen
-
Mike Stewart
-
Roger Breton
-
Steve Upton
-
Terence Wyse
-
Todd Shirley