Prepress Color manaagemet Feedback

amybest222

Well-known member
Recently asked to start documenting the "Color Management procedures" in pre-press to be incorporated into our written ISO procedures
Would love some feed back and suggestions..

this is just for Color Management- not the whole preflight process- looking forward to feed back

1. All Clients and jobs are handled with the same due diligence and process in regards to color management, evaluation and execution of such process.
2. Production “plans” and “reviews” with management and prepress before a job is brought into preflight, especially when images are “high-end”, need possible retouching or conversion from RGB.
As a standard:
• Resolution checked
• Maximum Ink Density Checked (Under Color Removal)
• Color Balance of Images Checked
• Gray balance of Images Checked (Gray Component Replacement)

Preflight, before releasing POC lasers and preflight report (containing color separated lasers if the job contains spot colors), reviews all file content with shift manager.

Images and Color Management of RGB to CMYK
1. Hi end fashion and makeup with RGB images are converted by applying to “assign profile” to Coated Gracol 2006 (ISO 12647-2:2004) in Photoshop or in the Indesign Pdf Process. This allows for minimal to absolutely NO color degradation in the conversion process.

• A proof is output of the original file before any changes made within the department. A second proof is made for comparison after corrections to the file.

• When a customer supplies “Match Proofs” the house proofs are reviewed with management for accuracy before releasing to production.

• All Spot colors within an application are set to display at “Lab Values”, which is a requirement by Pantone certification. This allows for the most accurate display and representation from the application to the proofing process.

• Every proof that is output in the Prep department has the New IDEAlliance ISO 12647-7 2007 Color Control Strip and is read and verified to be in compliance and within G7 standards. Each proof is labeled for color verification and identification.
 

Stephen Marsh

Well-known member
amybest222, I think that your posted draft needs major editing and revisions. I have been in your position before, documenting prepress work processes for ISO certification (yes, we passed! I believe that we were the first such company to do this in our field in Australia, back in the mid 90's). I am only going to single out one section to start with:

1. Hi end fashion and makeup with RGB images are converted by applying to “assign profile” to Coated Gracol 2006 (ISO 12647-2:2004) in Photoshop or in the Indesign Pdf Process.

This reads wrong. Assign and Convert are two different things which are often confused by end users. Assign is simply a label or tag, it is metadata describing the current appearance of the file. The device values or file values of the image/data are not altered or changed with the Assign Profile command. Convert will change the values in the file, attempting to retain the original appearance of the source in the destination.

If you have RGB images coming in, you basically have two options:

i) If the RGB data contains an embedded profile - then you either choose to honour that profile or ignore the customer's profile (description, label, tag) and assign an alternate profile. The RGB could be assumed, as is the case with "no colour management" - however a source is always being set somewhere, either explicitly or implicitly.

You have to decide what your Adobe Colour Management Policies are in regards to honouring colour profiles and overriding colour profiles with explicit or implicit workflow settings.

ii) If the RGB data has no embedded profile (no description, label, tag) - then you will either have to explicitly Assign a profile, or implicitly assume a profile with no colour management (which will use your RGB colour settings for the assumption of the description, label, tag).

Once you have your source RGB input decided, then you would Convert to Profile, using Coated Gracol 2006 (ISO 12647-2:2004) as the destination for the conversion.


This allows for minimal to absolutely NO color degradation in the conversion process.

I can't agree with this statement in regards to RGB to CMYK transforms - either in theory or in practice. I would ditch the whole sentence and make no claims, simply state the workflow.


Regards,

Stephen Marsh
 
Last edited:

amybest222

Well-known member
Hmm thanks for the input -i will ditch the whole statement and change assign to convert..
Basically we are seeing much sucess with this process ( allowing the destination profile to be Gracol...) in preserving numbers
But i hear what your saying i willl ditch the whole line..
Also we are ISO certified they are just adding color management policies in. Any wording is appreciated.
 

Stephen Marsh

Well-known member
Hmm thanks for the input -i will ditch the whole statement and change assign to convert..
Basically we are seeing much sucess with this process ( allowing the destination profile to be Gracol...) in preserving numbers
But i hear what your saying i willl ditch the whole line..
Also we are ISO certified they are just adding color management policies in. Any wording is appreciated.


Ah, there are different ISO certifications. The ISO certification that I was referring to was the general one for manufacturing, I can't remember the code... This was before standard print conditions were the norm. One had to document all of the workflow practices step by step.

With RGB data, you can't assign (label) a CMYK (GRACoL) profile, so the process must be to convert and the device numbers/values in the data will change.

Before you can convert to CMYK, the "flavour" of RGB has to be set, either implicitly (no colour management, assumed profile as per colour settings) or explicitly by honouring an embedded profile or manually overriding the customer profile with a profile of your choice.

With CMYK data, you can of course "label" the data with GRACoL without any change to the device numbers in the data.


Regards,

Stephen Marsh
 

rich apollo

Well-known member
Basically we are seeing much sucess with this process ( allowing the destination profile to be Gracol...) in preserving numbers

As Stephen said, this isn't possible. In Photoshop "Preserve numbers" is a function of soft-proofing and is only available when the file and the soft-proof condition are using the same kind of colorspace, i.e. both in CMYK.

In InDesign, in the PDF export process, there is a setting "Convert to Destination (Preserve Numbers)". This gets more complicated. In going out to the GRACoL_2006 colorspace - CMYK Illustrator elements are unchanged. Grayscale tiffs and PDFs are unchanged. CMYK tiffs with an icc proflle differing from the destination colorspace (GRACoL) are converted. Native InDesign elements in CMYK will be unchanged. RGB images are converted. The rendering intent used can change from item to item. The default is the rendering intent set in your Color Settings, but a different rendering intent can be assigned to every element.
 

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