Differences in proofs to offset and coated stocks

[publicsectorslave]

Recently, running into issues with customers complaining about the quality of proofs compared to quality of press sheets. We only have SherpaProof Base Satin paper that we print through an Epson 9800. We are running an Apogee X system to an Avalon/Azura.

The proof look immaculate and sharp and the designer signs it off without any reservations. Yet when the customer wants the job printed on an offset stock the printed results are barely acceptable. Our pressman runs set-up sheets on a variety of stocks some of which are coated and those match the proof, but the image quality severely degrades when running the job on the customer specific offset sheet.

Are we giving customers/designers false hopes by printing their job to a coated proof sheet, but instead should be printing to an offset proof paper (any paper suggestions in the Agfa family)?

Or is there anywhere I can globally apply a curve to adjust all the images to print to the proof paper as if they are printing to an offset paper. (maybe increasing the Dot gain?)

Thanks in advance.

 

[Colorblind]

Seems like you'll need to change the profile you use in the Press tp of your ApogeeX ticket. I suggest you try different profile combination, set your rendering intent to "absolute colorimetric" in your proofer tp (so you get the paper tint simulated on your Epson) and see if you get a close enough match. If that's the case and the match is not perfect, you can always edit the profile (given you have the appropriate tools to do so). Else, you will have to make a new profile for that press-ink-paper combination. If you are not familiar with the procedure, I suggest you call your Agfa rep or hire a consultant. Good luck.

 

[publicsectorslave]

Thanks colorblind for the push in the right direction....
Any good "educational" sites or books on profiling available?

Called Agfa earlier but its' a holiday in the US (I'm in Canada). Had other jobs to process so didn't want to wait on hold. Although I was a member of the Apogee User forums, everytime I try to access it, it leads me to a "forum not available message" ( AGFA.com - Apogee forum not available... Sorry )

I'll make sure to explore the task processors on Monday to see if an uncoated profile was made by Agfa when the new system was installed/job-ready in July of this year.

thanks again

 

[botas]

Profiling this has been a nightmare for us for the last 10 years (colormangement) if we take one step back into 1990 how did we match color on a press we were given a chromalin which the pressman tried to match, no standard to follow.The proof was when we sent the same set of films to 4 different Reproduction houses and what we got back was 4 different Chromalins. 10 years later and we are seeing the same results a file sent to 4 different printers and we get 4 different proof results.
Finally we had to put a stop to all of this and what we did was to created 3 different characteristic curves for our presses one for coated paper, one for uncoated paper and one for newsprint stock.

We then printed a test sheet for the different stocks and we printed to ISO standards density and dot gains.
One we had one of these test sheets we created an ICC profile for our Epson 9800, so now we have a profile for a coated, uncoated and newsprint our proofs match our presses.

All our clients approve their proofs under light booths, which have the correct lighting and our print results are 95%-98% correct we have stopped all the nonsense with our clients of saying that the proof does not match the printed result.

In order for us to keep this standard we have to stick to a set of rules when it comes to the press, the printing press is the mechanical giang which keeps changing if you do not stick to the same inks and the same blankets etc. etc.then the results are different.

From then onwards the dog wags the tail not vise versa, as i said, for 10 years we kept going back and forwards with various suggestions from different suppliers, now job after job and and we have no problems.

We have presses from different press manufactures however we have a Heidelberg CTP workflow. We contacted them with our problem and they came up with the suggestions . Give them a call they have some outstanding tools for color management. The proofers ( Epson Canon or HP )are not the problem their result are constant provided you use the correct paper and the recommended inks its the press that you have to constantly monitor, that you are printing to a standard( you choose the standard)

This has been our experience it has been a costly one, we had our fair rejects from advertising agencies, we know all about color matching.

 

[Mike Strickler]

Just to expand a bit on what's been said: So long as the proofing stock isn't dramatically shinier or duller than the target press substrate, abs. colorimetric rendering will allow you to simulate the press paper color. Be sure that the source/reference profile is correct for the press and paper type bing simulated It is normal to have to edit the white point of the reference profile for a good match on paper color as most press papers aren't precisely GRACoL, SWOP 3, etc. Your proofing system should be verified as hitting the numbers for the chosen pres reference; otherwise the proof is just another moving target. You can buy standalone apps for this.

As for the press side, botas has it exactly right: Don't let the press be the tail that wags the dog. It should be run to the numbers, and only slight tweaking should be required to get very close to the proofs, again assuming the proof can be verified as accurate to the relevant standard and reference profile.

Good luck,

Mike Strickler
Certified EFI Colorproof installer and trainer
Idealliance G7 Expert
MSP Graphic Services: Prepress and Color Management

 

[Lukas Engqvist]

We have some customers react that our proofs on satin are drab when proofing for uncoated, but comparing dry print to proof has helped them understand that the digital proof is far superior to the chroma in simulating what the dry result will look like.
We did have a time when we proofed uncoated work on a paper with more "uncoated" surface, but switching rolls is not practical, and we have been able to show with a track record that proofing for uncoated works fine even on satin.

 

[publicsectorslave]

Thanks for all the replies. You sure did point me in the right direction.
The Task processors have revealed some hidden gems in them - lots of variables, just gotta figure out the right combinations.

Overall though, not impressed with Agfa's telephone response (even with a multi-year $XX,000's service contract) when I finally called. I had an idea what needed to be done, but getting a "hire a specialist", "we don't provide telephone training" and "no, we only provide support for agfa papers" was unexpected. Not much documentation provided with the install and nothing at the Agfa website either - save promotional stuff.

Thought Agfa provided a workflow solution, not just equipment.

My supervisor has a call in to Agfa for any remaining "training days" to be used for automating, profiling, archiving, and backing-up all the data off our windows server.

Thanks.

 

[past_print]

As we tell customers, it's to show color seps, not for exact representation.
We don't EVER change stock in our epson.
It's not a press proof, just for color seps and content.
(unless digital printing. Then we use appropriat stock, etc...)

 

[otherthoughts]

publicsectorslave

Proofs not matching the press have been the bane of printers since proofs were created separately from the press itself. Before the split between press and proofs, we had "press-checks" or "progressive proofs" only.

The good news for modern times, is that great progress has been made since those days. Device profiles and color management technologies address color management issues handily within the scope of their control. Properly implemented and understood, these tools are as good as it gets today. It's the best we have seen since the proof and press were first separated from one another.

The baggage accompanying this new technology is creating all the necessary device profiles.

I get my brain around D-Max(density maximum) better than I do color spaces.
D-Max is a log-10 scale, which means that a D-Max measuring 3.0, has ten times the density(color space) of a D-Max measuring only 2.0.

Film and digital cameras typically live in the 3.0 D-Max range.

Gloss coated press sheets and gloss coated proofs congregate near the 2.0 D-Max range.

Uncoated press sheets and uncoated proofs live around the D-Max 1.5 range.

At the bottom of the D-Max scale is unbleached newsprint and proofs upon such stock, they perhaps achieve a D-Max of 1.35.

You can obviously emulate a smaller color space(D-Max range) on a device that is capable of a larger range(using the right device profile of course).

Attempting to emulate a larger color space utilizing a device capable of just a smaller color space(D-Max) is the real service(education) you provide to your customers, when they complain about their reds, blues, etc. not matching.

So "publicsectorslave", selling a proof that does not emulate your press is of little value to you. It would seem that the device profile you have created for your press when running the customer's intended stock and the appropriate ink set is sadly not reflected in the proof you've shown to your customer.

What I am really saying here is that your Epson proofer should be able to emulate any color space equal to or smaller than it's capabilities when provided with the appropriate device profile. The Epson's absolute color space will change according to it's input stocks and consumables. With the Epson's "best coated stock and inks" it's proofs should be able to emulate reasonably well most press results on any coated stock. Uncoated stocks and newsprint on the press might be better represented by the Epson with similar types of stocks.

No matter what you do, a press or Epson proof will not attain the 3.0 D-Max color space of a Camera.

I hope this helps to clarify a bit? Maybe not?

The fabulous sunset that a photographer saw, shrunk when he photographed it, shrunk again when you proofed it, and hopefully shrinks no further when you attempt to print it.

The post by “botas” seems like a logical approach towards a solution and stability to me.

 

[gordo]

The proof look immaculate and sharp and the designer signs it off without any reservations. Yet when the customer wants the job printed on an offset stock the printed results are barely acceptable. Our pressman runs set-up sheets on a variety of stocks some of which are coated and those match the proof, but the image quality severely degrades when running the job on the customer specific offset sheet.
Are we giving customers/designers false hopes by printing their job to a coated proof sheet, but instead should be printing to an offset proof paper (any paper suggestions in the Agfa family)?

A "contract" proof is a communications tool that sets customer expectations by simulating the final presswork. (That does NOT mean that the proof should match the press nor that the press should match the proof - i.e. the dog or tail wagging argument)
If you supply, or receive, a proof that will not align with your press work (i.e. proof simulates the presswork on gloss paper but you're printing on uncoated) then it is your responsibility to advise your customers about the disconnect accordingly. It is then your duty to communicate, by whatever means are appropriate (samples, press test, educational literature, etc.) the nature of the disconnect so that the customer can make a reasonably informed decision as to whether they should proceed or not.
It does not really matter what method you choose - the important thing is that the communication occurs and that it is documented in the job history.

best, gordon p

my photos here: Gordon Pritchard's Photography
my print blog here: Quality In Print

 

[destryer]

RE: Differences in proofs to offset and coated stocks

We ran the same stock you mentioned. It's the only one certified for SWOP from a Agfa If you build press profiles and load them at your pressTP you should get the correct look of subdued d colors from matte, uncoated and gloss stocks when you build your color profiles. You have to explain to sales , marketing a and the client that the stock is a substrate the profile simulates the look of thei ink on paper.
Good luck you have a lot of arguing to do!