Fix Total ink coverage Video Tutorial

[juliane]

Hello everyone,

I have problem in fixing total ink limit in photoshop often the color changes. Today i saw a video in youtube here is the link YouTube - ACE UCR Fix is their any one who tried this method ?

juliane

[Lukas Engqvist]

I would normally fix an ink problem by applying a devicelink if in photoshop.
An alternative is to convert the image to ECI-RGB and then reseperate to CMYK with a more appropriate separation profile. If I do layout in InDesign I will normally actually stop at converting the image to RGB and then apply the correct TAC CMYK-separation when creating a PDF.

Alternatively configure the PDF print engine (in Apogee) to do repurposing.

[gordo]

An alternative is to convert the image to ECI-RGB and then reseperate to CMYK with a more appropriate separation profile.

This works very well (and is simple) because the vast majority of CMYK separations today use GCR not UCR (as the video suggested). Original separations with GCR have much smoother tone transitions than UCR and as a result convert very well back to RGB and back to CMYK with a different TAC setting. Doing the CMYK to RGB to CMYK should not affect color. It's also easy to automate the transformation in PShop.

best, gordon p

[Stephen Marsh]

Hello everyone,

I have problem in fixing total ink limit in photoshop often the color changes.

Juliane, you mention the colour changing. How are you currently altering the total ink limit of incoming files? Are you changing the entire file, or only the shadow and three quarter tone transition areas?

Do you work for a newspaper or on more challenging substrates? What is your total ink limit and what is the common total ink of supplied files? I presume that you have tried educating your customers on RGB file supply or correct supply of CMYK and that you are still forced to deal with this issue.

Today i saw a video in youtube here is the link YouTube - ACE UCR Fix is their any one who tried this method ?

juliane

No, I have not tried this particular method, however I presume that it is very similar to other free photoshop ink limit selection methods available (although it appears to be a bit more refined).

As this is an action for sale, one can't trial a demo of the product, one only has the video to go by to see the workflow. I would contact the developer and get them to reduce total ink in some of your sample images, to see if they do a better job than your method or other available methods.

For high volume or high quality alteration of ink limits, most would use a device link profile or other more expensive method.


Stephen Marsh

[Stephen Marsh]

Lukas, Gordo -

The DVLP route seems safe, with no issues of affecting pure primary and secondary colours.

To play devil's advocate on the CMYK to PCS/RGB to CMYK conversion...

What would you do if the image was device CMYK, untagged? Converting from CMYK will assume a CMYK source profile - yet the source is unknown. This has the potential to seriously change the colour in the file, not just the shadows.

Or would you somehow limit this change to just the shadows and darker tonal transition areas (blending it back into the original), so that you were not "trashing" most of the original separation and altering the intended colour in non shadow areas?


Stephen Marsh

[juliane]

Hi Stephen Marsh,

Right now iam checking my image's acrobat and making correction in photoshop in selected area it works good but takes time also. I work for packaging products an they require 280% as ink limit

regarding profile convertion i tried it but color changes drastically i will try new profile suggested


Juliane

[Stephen Marsh]

Hi Stephen Marsh,

Right now iam checking my image's acrobat and making correction in photoshop in selected area it works good but takes time also. I work for packaging products an they require 280% as ink limit

regarding profile convertion i tried it but color changes drastically i will try new profile suggested


Juliane

Juliane, as I was alluding in my reply to Lukas & Gordo, I would not re-separate the entire file if going down the "standard" CMYK > PCS (or RGB) > CMYK route. Unless done well, there are too many problems with re-separating the entire file when it is only the shadows that are an issue.

I would work in a dupe, convert that to another profile, then blend in the new conversion as a layer over the top of the original conversion. The new layer would be masked, so that only the neutral shadows from the re-separation were being added. The majority of the original separation would be used, one is just replacing the shadows and close tonal transitions (no point throwing the baby out with the bathwater). The CMYK destination profile would of course need a 280% TIL/TAC/TIC value.

If there were areas of deep hue/colour that were over the total ink limit, like a deep blue, then I would make selective edits to such colours as needed.

If you have the budget, then getting into device link or other image ink editing software would be more productive and would provide better results. Even with a lesser budget, a consultant can build and licence you a device link profile, which would bring down the costs compared to buying DVLP software outright (enter Matt Beals). You would need Photoshop CS4 or a RIP capable of using CMYK to CMYK device link profiles to directly convert CMYK to CMYK (bypassing the standard ICC profile PCS).

I previously mentioned a less refined, but free total ink limit action. This action can be found here:

http://www.curvemeister.com/download..._tac/index.htm


Stephen Marsh

[Lukas Engqvist]

For best results use relative conversion with black point separation.
If Device CMYK I will normally assume the CMYK to be the same as the stock/process.

I normally convert the whole image. If change happens it is in the convert to CMYK stage. In case of converting to uncoated it is possible use the proof preview to access if any adjustment (as possibly increase contarast, to compensate for loss of contrast in next stage, I prefer shadow highlight for that).

The quality of your RGB to CMYK profile does affect the process. We use a profile that is generated from ISO measure data but with TAC 280%.

Now if there is areas of significant change and this has been done in one layer file, you can "fill with history" to get back original image and use the "fade..." command to select a different blend mode, eg luminosity or just back off to a % to compromise the first and last state. Coulours would i assume get most changed in dark saturated colours? Is this evaluated on screen or on print?

It is a problem that readilly available profiles have too high TAC.

Sorry forgot to mention if you have a LAYERED file then you may need to flatten (or convert to smart object) first since blending modes are very different in CMYK or RGB.

[mattbeals]

Someone call me?

Device links with or without ink reduction are definitely possible. If you need a sample processed through a link I can do that for you.

As Stephen said there are many ways to apply the device link. If you have a RGB to CMYK link then you cannot use it in PhotoShop CS4. But a CMYK to CMYK link you can. Such a link, CMYK to CMYK, can be used in most all RIPs, PhotoShop, callas pdfToolbox, Enfocus PitStop, etc. Just depends on what you have. Depending on the level of logic in the program, like in callas pdfToolbox, I can apply the link to only the objects that exceed a given threshold so that I don't "tinker" with objects that I do not need to.

All depends on how you want to do it.

[Stephen Marsh]

We use a profile that is generated from ISO measure data but with TAC 280%.

Lukas, the lowest TAC ISO profile that I have at hand is the ECI ISO v2 300 TAC...is there any chance of you sharing your custom 280 TAC profile with the forum?


Stephen Marsh