Should i convert job/PDF to desired out color profile befor sending to RIP or not...?

[andy_baz]

Good Afternoon,

Background Info
I am pre-press originator with 15 years experience in the trade but only recently trying to achieve a (properly) color managed workflow.

I create print jobs in InDesign for out putting to our printing presses. Presses being A Komori lithrone 26 and a Sanxin YK524.

On both presses we run full colour jobs on both coated and uncoated stocks.

My Workflow
From Indesign i Export PDF's into our Momentum workflow(which i believe is a harlequin RIP badged as Momentum RIP).
In the Momentum workflow i have 2 print queues for each press: Coated and Uncoated.
Both presses run a two curve operation (rightly or wrongly il'll let you decide) with the plates being linearized and then adjustments added as per the Intended and Actual Curve settings.
The intended curve for Coated is FOGRA 39 ISO A Standard
The intended curve for Uncoated is FOGRA 29 ISO B Standard
The actual curves have been produced from linear plates and dot gain values entered accordingly.

Should i convert job/PDF to desired out color profile before sending to RIP or not...?
By this i mean before pacing my pdf into the workflow should i be converting the pdf to the intended profiles?

For example my InDesign colour management destination settings are set FOGRA 39 Coated jobs, so im wondering if for Uncoated jobs should i be manually Converting the PDF to the FOGRA 29 profile then placing into my workflow Uncoated print queue ready for outputting plate?.

I currently exported unconverted PDF's fro indesign and let the RIP adjust the values accordingly for each queue but im not sure if this is correct.

I hope i have explained this correctly and have covered all areas i need to, feel free to ask for more information

I eagerly await your answers and opinions, and will be very grateful to those who respond.

Andrew Barrington

 

[Glenn McDowall]

I'm assuming the plate curves you mention are calibration curves and your RIP is not Profile converting.

In theory converting to Fogra29 when you make the pdf (or maybe better to make the conversion in Acrobat) will change the numbers and hold the appearance for printing on uncoated stock.

This would be a big argument to do so.

However there are lots of little arguments to carry on not making the conversion.
Black generation, or keeping tints of just black as just black can be tricky, to implement this less crudely you need a DeviceLink profile which are not cheap.
Reprints, would be unlikely to match.
On Screen appearance in Acrobat can be off-putting to clients.
FOGRA29 is an average, unlike coated stock, uncoated can vary a long way from this average. In some cases doing the conversion may make thing worse.

If you are always using the same uncoated stock for everything, its probably worthwhile. If you are using a variety of stocks AND a job is colour critical I think its more economical to wet-proof.

 

[rich apollo]

InDesign will pass gray elements through, so maintaining your black channel is not a problem. I think that the only thing you need to convert are placed elements; RGB photos and the like. If you use Convert to Destination (preserve numbers) then elements that are native InDesign elements will pass through untouched, placed CMYK elements that do not have an embedded ICC profile will be passed through, placed CMYK with an embedded profile that matches the Destination profile will be passed through, placed CMYK elements that have an embedded profile other than the Destination profile will be converted, and RGB/Lab elements will be converted.

I think this strategy would give you what you need.

 

[Glenn McDowall]

I think that the only thing you need to convert are placed elements; RGB photos and the like. If you use Convert to Destination (preserve numbers) then elements that are native InDesign elements will pass through untouched,

On the one hand this is a perfectly good strategy, on the other hand background tints that would be better off converting don't get converted.
If I was playing devil's advocate I'd say this is a bad idea because you are arbitrarily choosing to change only half the job!
But, it is often the way I would create a pdf if presented with InDesign files. It is also the way I'd recommend a client create their pdf.

There will always be jobs which don't fit the norm.

 

[rich apollo]

Glenn, I recommend this strategy because the OP is designing the files. My answer is based on the assumption that he is designing in the colorspace he that will be used. If he is designing in FOGRA39 for an uncoated printing, then you are right, he should consider converting everything.

 

[andy_baz]

Thank you guys for your replies they have been most useful,
here are some screenshots of current settings i use or intend to use
These are my Suite Color settings

 

[andy_baz]

My PDF output color settings

 

[andy_baz]

and this is the way i would convert to the uncoated profile in Acrobat

 

[andy_baz]

Basically my process goes like this...

Combine all the design elements in indesign, images would be tagged with the color profiles, then export to pdf with no colour conversion, then drop PDF into my Workflow for Ripping and outputting to plate.

What i was confusing me was that by default my color suite applications use Coated FOGRA39 as a default color4 setting which is fine for outputting Coated Jobs, but when i have the same design elemtns need outputting for an Uncoated FOGRA29 job i wandered if convesion was needed and if so when to apply it. A question i feel has now been answered.

My only query now is if i am converting to the Intended Uncoated FOGRA29 Profile, and sending my converted PDF to my Workflow Print Queue... is my Uncoated FOGRA29 Workflow queue now doing a second conversion as the harlequin rip is set to Intended FOGRA29 settings or is this still necessary as it is bringing the dot gain values into line with my intended output....?

Hope this makes sense

Andy

 

[Stephen Marsh]

Andy, let’s back up a step or two and try to keep this simple, before making things more complex, as you may not need to…

If you submit a F39 file to your F29 queue, what if anything is unacceptable about the result? How different does the end print look compared to a proof correctly prepared to show content in F29? You mention you have curves applied, do these not take into account that the source is F39? Or are the curves presuming that the source is correctly setup for F29?

For comparison, how does your F39 proof look compared to the F39 press results? Is it close for tonality and colour?


Stephen Marsh

 

[rich apollo]

I see some issues:

1) You're not including any profiles in the PDF. I feel that this is a mistake.

2) The conversion you have set up in Acrobat will not preserve your black channel. You're going to get 4-color blacks

3) I think you're converting to FOGRA39 and then to FOGRA29. This is not necessary.

4) Because you haven't included any profiles in the PDF, the source profile will be the default in your Color Settings.

I agree with Stephen that you may not need to convert at all. There are only two things that NEED to change between your coated and uncoated jobs: 1) the plate curves and 2) the source profile for proofing.

 

[Stephen Marsh]

2) The conversion you have set up in Acrobat will not preserve your black channel. You’re going to get 4-color blacks

Further to Rich’s comment above:

Preserve blacks is checked – however this will only retain black only text and vectors, NOT smooth shades/gradients and rasters.

This is better than nothing and better than performing a device ICC conversion alone, however it is not as good as using a dedicated devicelink profile that has been constrained to retain solid primary colours and or maintain the entire K channel, regardless of the content being vector or raster.


Stephen Marsh