proof printing
making and testing an ISO Standard Proof
Why make an ISO standard proof? Why test an ISO standard proof?
We start with an image file, which is perhaps intended to be part of a press ready page. It's useful, of course, to have a prediction what's going to happen when this image goes to press; just how will the image be reproduced? Softproofing (i.e. on screen proofing) is useful during colour correction etc. and it can help a lot, but a printed proof is great to have when possible. Especially an ISO standard proof. In a press preparation scenario a poor looking proof begs a question, could we improve reproduction using some simple Photoshop adjustments to the elements at this stage - often the answer to this question is yes. It's FAR better that way than leaving the press operator to attempt to fix issues on press. Get the proof right and the print will be right if the process is set up well.
how will the job be printed, how should it be proofed?
IN order to proof well, it is important to know a little about the printing process that will be used - perhaps the job is destined for a magazine, thus, normally, printed using a “web” press (i.e. on a continuous roll of paper), or perhaps for a shorter run on a “sheet-fed” press. It could even be a Gravure job (short for Rotogravure).
Or perhaps your job is for Newsprint? In the above types of printing, there are "standards" which press operators can work to meet and CMYK separation ICC profiles are available for them all. ICC profiles from ECI here. These same ICC profiles are invaluable for proofing.
the value of press standardisatio
The work that's been done on press standardisation is very useful to designer, image originator or editor, because if we know that the eventual press will be run well, "to standard", we can be confident that the freely available standard ISO profiles will represent that press well. So, a good proof can be made and a good separation (from RGB to CMYK) can be made using those standards based ICC profiles - when proofing, these profiles are used in tandem with the ICC profile that defines a well calibrated desktop printer. This way, the final print can be predicted well and, if proofs are good, we can be sure that what goes onto the printing plates actually suits the printing process.
is the proof just a pretty picture?
I have heard it said in Germany that “There is no proof without an Ugra/Fogra Media Wedge, it's just a pretty picture”. This statement suggests that without some form of standardised control strip which can be measured, first by the proof's producer and later by the recipient of the proof, any printed image can only be considered as a nice picture. In many ways that is true. What we see on the proof may or may not relate to press output, so, no matter how nice it is to look at, it's not guaranteed to match a properly done print job. If that's the case - it's not much use as a proof.
the Ugra Fogra Media Wedge control strip
My tech. partners basICColor, working in conjunction with industry standard bodies Ugra and Fogra, have developed the basICColor Control software to provide the tools to measure the Ugra/Fogra Media Wedge on each proof.
This officially sanctioned control strip can be measured with a simple hand held spectrophotometer - analysis software then provides information about proof quality. The proof quality is assessed by comparison to the relevant reference data - data which was gathered from an actual standard press run (this is the same standard press run that made the CMYK separation and proofing profile). Now, anyone receiving a proof showing such a control strip and validation sticker can know or sure that it's not just a pretty picture - they can know with confidence that it truly does relate to press output.
This is the future of proofing, working to proof to an open, internationally recognised, non proprietary ISO standard, based on real world printing press performance.
how does the Ugra/Fogra Media Wedge work when proof checking?
the process starts with measuring print from a standardised press.
Firstly, a standardised press is "characterised", perhaps by the experts from BVDM, ECI, Ugra, Fogra or GRACoL. Press data, which "fingerprints" or "characterises" the press, is a gathered by printing a standardised target - comprising an extended CMYK patch-set and reading the target from the press sheet with a high quality spectrophotometer.
This measured characterisation data has three important uses:
1: The colour accurate numerical patch data shows exactly how the standard press will reproduce certain CMYK colour ink recipes. These same numerical values are used as a target reference when measuring an Ugra/Fogra Media Wedge on a proof to compare proof colour to press colour.
2: The characterisation data is used as the basis for making the CMYK ICC "separation" profiles that will be used to make press ready files from RGB originals.
3: Characterisation data is used within the proof printer software to produce the proof that is a good match to the press output.
press simulation in the proof printer:
When printing proofs, we use both products of the characterisation process, the ICC profile and the reference data.
Original RGB data is separated (converted) to press ready CMYK using the ICC profile. Adobe Photoshop can do this.
The same CMYK ICC profile is used in the proofer RIP software to tell the colour management system how to simulate that specific press output.
measuring the Media Wedge
The Ugra/Fogra Media Wedge on the printed proof is measured and compared against the reference data produced when measuring those same CMYK patches that were printed on the standardised reference press at the time of characterisation.
Simply put: the Ugra/Fogra Media Wedge contains a sub-set of the patches originally printed at the press.
So, after measurement of the proofed wedge, an accurate comparison can be drawn between proofer result and press result. ISO has specified tolerance figures for use as guidance in comparing measured proof colour and measured press colour.
Basically, that's what the Media Wedge is all about. Checking a properly made proof against accurate press results; a pass means the proof is good and can be trusted.
making an ISO proof, the practicalities
hardware and software
I am seeing excellent results from Epson's machines, e.g. 4900, 7900 and larger. Many high end pre-press studios are turning from rather expensive proprietary proofing systems to far more cost effective set-ups of Epson hardware and decent RIP software producing very accurate proofs. This quality is evidenced in the Wuppertal proofing shoot out which used the Altona test Suite.
As a result of these initiatives, I am pleased to see that open standard print and proofing really is taking off.
software RIPs for proofing, or for photo reproduction?
I've spent a lot of time researching the ins and outs of various printer RIPs with proofing AND photo reproduction in mind. Not many RIPs can do both. I now have solutions that, in conjunction with Epson's inks and the right paper, as well as making excellent photo-quality art prints, also allow us to produce decent proofs.
how can I help you?
I can provide any component part or a complete package of Epson printer and proofing and / or photo RIP and the on site optimisation and training as well as the necessary ink and paper.
The colour management part of this service is basically on various levels.
On site work is carried out to linearise and profile the RIP and printer to perform to the ISO proof standard.
Planned site visits ensure continued accuracy.
Training in the maintenance process is also an option, for those who prefer self sufficiency.
For critical applications I recommend training in the use of the basICColor “Control ”application - and that the Ugra/Fogra Media Wedge be placed on every proof.
Alternatively, I can measure a Media Wedge on installation to ensure accuracy - and, later, re-measure at an agreed period to keep an eye on proofer performance.
You can get in touch via this link.
:: Fogra ::
