TAC Trueflow 7

[fredfish]

I have a file with 350% tac i dark areas. Want to reduce this to 300% without changing colors.

The images in the PDF are not tagged. If I tag images using f.ex ISO Coated v2 300%, the colors will come out at 280% in the RIP-ed Proof PDF in Trueflow. But in Acrobat's Output Preview simulating Adobe CMYK it comes out as 312%. If I simulate ISO Coated 300% nothing changes. Still 350% tac.

Thanks a lot

 

[Lukas Engqvist]

If the images are 350% TAC I would probably tag the file with ISO coated and then repurpose ( using Acrobat's colour converter) to ISO Coated 300%, preserving black and pure colour. Or I would use a device link. I do not have trueflow but just trying to be helpful.

More commonly, I would only tag the images that have too high TAC to avoid any unnecessary conversions.

 

[fredfish]

Thanks a lot.
But Acrobat adds heavy compression to the pictures when converting. There might be a setting for this somewhere I can't find.

I just got PitStop 10 Pro, it might be better to do it here, or what do you think? I just can't find my way around it to get it right.

In my RIP I only have Device Link for rgb2cmyk. I'm not familiar with that workflow, but the result doesn't look very good, so my guess is that I should pass all colors thru, and do all converting in advance.

 

[TerryWyse]

You absolutely can use device links with Trueflow. Where I've implemented them for my clients is in the jobs ticket where you "execute" a plate to be imaged. There's a color management section in there where you can select from a list of device link profiles that have been installed on the system. Works extremely well in my experience.

Regards,
Terry Wyse

 

[fredfish]

Forgot to thank you, Lukas and TerryWise.

I just had my Trueflow set up with Device Links. Works good so far
A couple of more questions for you Terry (or anyone else using Trueflow)

1) Do you know a way to see the conversion results in Proof PDF? Under "Color Management" in Proof PDF, Device Link profiles won't show. I have to add a TIFF before the Imposition, and then open in RIP-Viewer. This makes the RIP take more time, since I also need the ProofPDF anyway, plus I like to see the colors in Acrobat.

2) Device Link works great for cmyk2cmyk. BUT what would you say is the best way of handling RGB in Trueflow? It seems that it has to be converted to Adobe CMYK first (in Input), and then using a Device Link to reduce TAC in the RIP-For-Recorder.

3) I have got ISOcoatedMax280, ISOcoatedMax300 and ISOcoatedMax320 Device Link profiles. Does anyone have or know where to find DL profiles for Uncoated paper? Yeah, I know that the TAC in ISOcoatedMax280 should be fine for Uncoated paper, but the Dot Gain won't be correct if I'm printing on Uncoated. Or am I wrong?

Thanks again, folks

 

[rich apollo]

fredfish,
A coated profile for uncoated work is not appropriate. Yes, you can reduce the total ink this way, but yes, your files will still be too full on uncoated paper and you won't get a good representation of the color that you will see on press.

Not sure what you're wanting to see with the Proof PDF. If you simply proof the file that after you've converted, then you'll see what you've achieved. Or are you trying to run this device link conversion at the time that you're plating? I know that Terry has had success with this idea, but it's just not one that I can run with. I insist on proofing what I'm going to plate. For that reason I handle this conversion upstream from the RIP.

As for your RGB elements, you can upload whatever ICC profiles you want to your Trueflow RIP, however, I would recommend handling the conversion of these elements in Acrobat. You can set up a conversion for RGB elements only.

I ran a Trueflow RIP years ago, and while it's a solid system, it's not my choice for handling color. That's the beauty of using the device links - you get to take advantage of a superior color transform.

With all you've described, you've made a very solid argument for running a color server to perform these tasks - something like Alwan CMYK Optimizer or FineEye ICE.

 

[fredfish]

fredfish,
A coated profile for uncoated work is not appropriate. Yes, you can reduce the total ink this way, but yes, your files will still be too full on uncoated paper and you won't get a good representation of the color that you will see on press.

That's what I thought. But I've searched the web and I have asked Screen, and did not succeed in getting hold of ISOUncoated DL-profile.

Not sure what you're wanting to see with the Proof PDF. If you simply proof the file that after you've converted, then you'll see what you've achieved. Or are you trying to run this device link conversion at the time that you're plating? I know that Terry has had success with this idea, but it's just not one that I can run with. I insist on proofing what I'm going to plate. For that reason I handle this conversion upstream from the RIP.

We're running the Device Link when we're plating, but I'd like to see the outcome on screen first. We don't use a color proofer other than the monitor.

As for your RGB elements, you can upload whatever ICC profiles you want to your Trueflow RIP, however, I would recommend handling the conversion of these elements in Acrobat. You can set up a conversion for RGB elements only.

I've heard different opinions on this one. Anyway I wonder how I set up ICC in TF. In the Job Container's Input, we have a Color Conversion option under settings list. (See attachment) But the only option I have is "conversion method". And at the bottom you can see its target i Adobe CMYK.

Thanks a lot

--
Erik

 

[TerryWyse]

1) Do you know a way to see the conversion results in Proof PDF? Under "Color Management" in Proof PDF, Device Link profiles won't show. I have to add a TIFF before the Imposition, and then open in RIP-Viewer. This makes the RIP take more time, since I also need the ProofPDF anyway, plus I like to see the colors in Acrobat.

No clue.....but what you COULD do is simply run some sample images through Photoshop CS4 or later....CS4 and later now support device link profiles.

2) Device Link works great for cmyk2cmyk. BUT what would you say is the best way of handling RGB in Trueflow? It seems that it has to be converted to Adobe CMYK first (in Input), and then using a Device Link to reduce TAC in the RIP-For-Recorder.

Device links work great for rgb2cmyk as well...it's just that Trueflow doesn't allow you to use both.

I'm not intimately familiar with how Trueflow handles RGB.....but if it doesn't recognize or honor embedded profiles in RGB images, then it's a deal-breaker as far as I'm concerned. I'd go with Rich's suggestion of handling the RGB conversion upstream of Trueflow.

3) I have got ISOcoatedMax280, ISOcoatedMax300 and ISOcoatedMax320 Device Link profiles. Does anyone have or know where to find DL profiles for Uncoated paper? Yeah, I know that the TAC in ISOcoatedMax280 should be fine for Uncoated paper, but the Dot Gain won't be correct if I'm printing on Uncoated. Or am I wrong?

It's hard to know exactly what your current device links are doing (besides setting total ink limit). Just like any profile conversion, it takes "two to tango" and the same goes for device links, only in the case of links, you have a profile-to-profile conversion hard-wired into a single conversion table. My best guess is that all these "ISOcoated" device links used the same source/destination profile albeit with a total ink setting on the "back end". So these links are not changing or altering color, just re-separating for total ink limit and possibly adding GCR to the mix.

If you want something for uncoated that actually corrects for dot gain, you may need to create your own device link. If your press is currently printing to ISO Coated dot gain, then you would need to build a link using ISO Coated as the source profile and ISO Uncoated 240/260/280/whatever as the destination and build a device link out of it. In this case, it will assume all incoming images/pages were separated for ISO Coated dot gain conditions and then correct the output for ISO Uncoated dot gain....and it will reduce the total ink limit of course.

Regards,
Terry

 

[TerryWyse]

I've heard different opinions on this one. Anyway I wonder how I set up ICC in TF. In the Job Container's Input, we have a Color Conversion option under settings list. (See attachment) But the only option I have is "conversion method". And at the bottom you can see its target i Adobe CMYK.

Silly me...had I actually looked at your screen shot attachment, I wouldn't have needed to question whether Trueflow honors embedded profiles...it appears that it does (check that box!).

The biggest problem I have with that screen shot is that it appears to force a conversion to "AdobeCMYK", whatever the heck THAT is (in Adobe Photoshop, I see no profile called "AdobeCMYK"!). We could assume all sorts of things about what AdobeCMYK actually is...but at this point we don't know for sure.

In any case, if you can change that from AdobeCMYK to a CMYK profile of your choice (it would seem ISOCoated would make sense for your workflow), you might have a decent chance of getting a reliable and correct rgb2cmyk conversion done in the RIP. I would just caution that in-RIP conversions like that can be fraught with peril.....I'd still want to know upstream of the Trueflow that all RGB and CMYK conversions were carried out correctly and that everything has been "normalized" to the CMYK space that my in-RIP device links profiles are expecting.

Regards,
Terry

 

[fredfish]

The biggest problem I have with that screen shot is that it appears to force a conversion to "AdobeCMYK", whatever the heck THAT is (in Adobe Photoshop, I see no profile called "AdobeCMYK"!). We could assume all sorts of things about what AdobeCMYK actually is...but at this point we don't know for sure.

Yes, it's forcing to Adobe CMYK. Screen-representative says, and I quote: "The Adobe CMYK profile is a profile that comes with most applications and does not have a defined dot gain like f.ex. Fogra 39".
To me it sounds like the opposite of what I want.

If I could change that somehow, it wouldn't be necessary to use Device Links, or what? At least not on CMYK files that don't exceed 300% TAC.

I believe that the preferred workflow would be RGB directly to IsoCoated300/IsoUncoated270 instead of RGB>Adobe CMYK>Device Link ISOcoatedMax300. Or is last-mentioned a normal in-RIP conversion?

Thanks again