Parlons de Spectraproof : des faits concrets sur l'imperméabilité à la lumière

Par mbetz

In this short inverview, Matthias Betz of proof.de and Alexander Demmler of Lacunasolutions.com are talking about the topic of softproof and the Spectraproof softproofing solution in particular.

Matthias Betz: If we ask Google about softproofing, an article from print.de comes relatively high up, in which the eight most important softproofing softwares are listed, and then CorelDraw and Photoshop and Illustrator come next. You laugh. But what is the difference between these softwares and the softproof approach of Spectraproof?

Alexander Demmler: All these products, should they have a functioning colour management system, whereby I would grant this almost only to Photoshop from the list mentioned, are generally only capable of correctly displaying process data in cyan, magenta, yellow and black. All other combinations or even pure spot colours are also displayed, but never correctly in terms of colour. This is something where the domain for SpectraProof lies. And that is: All these products have a simple, classic ICC-profile based colour management, i.e. a colour management based on ICC profiles that only contain information for cyan, magenta, yellow and black.

With Spectraproof, we calculate the process colour component information from the ICC profile and take the spot colour information from a CXF4 file.

Matthias Betz: What CXF4 files?

Alexander Demmler: CXF4 is a data exchange standard to communicate colour information, and to communicate colour not only by LAB values but by spectra. And we take those spectra plus the spectra that we combine for cyan, magenta, yellow and black, and then we spectrally add it all up, and because we do spectral maths the end result is far better in the visualisation.

Matthias Betz: But that means Spectraproof needs a spectral file for the spot colour information?

Alexander Demmler: Right. Or an Oris Color Cloud access or a PANTONE Live access (which should come soon) and much more. Currently, you can also simply use a spot colour library in SpectraProof by measuring the spectral information from a fandeck with an i1Pro2 or a KonicaMinolta MYIRO1.

Matthias Betz: Does SpectraProof always require spectral data for the representation of spot colours or can you also enter a LAB value as a spot colour?

Alexander Demmler: Of course you can enter a LAB value, then SpectraProof calculates a spectra from it, or you can simply measure any colour. This is very easy: click on “Missing colour”, add colour, measure colour, and with SpectraProof you immediately have a very good visualisation.

Matthias Betz: Another criterion for Spectraproof are things like gold foil, silver foil etc. What other features are there for softproofing in SpectraProof that are not available in Photoshop and Illustrator?

Alexander Demmler: So the first thing is: if you want to illustrate a gold foil in Illustrator or Photoshop, you have to take a gold foil as an image, cut masks, and then you have to know Photoshop well to make a good masking and put the gold foil there. Spectraproof, on the other hand, takes the colour separation that the software generates, and the user just says: this colour separation will be the gold foil. And Spectraproof does the rest automatically.

Matthias Betz: And this works not only for gold foil, but also for various other things, right?

Alexander Demmler: Whatever the user has scanned or photographed.

Matthias Betz: What is already included in Spectraproof?

Alexander Demmler: We have already integrated various blue, green, various metal foils, uncoated papers, aluminium and much more. Especially with the uncoated papers you can simulate many things in the softproof.
Let’s take the structure of a print: there is the substrate, and possibly a primer or undercoat on some things in packaging printing. If you buy frozen vegetables in the supermarket, some of them are printed on brown kraft paper. To make the colours and images look right, white is used twice as a primer, only in the areas where the texts and images will be. And then a varnish is added on top. And there might even be one or more spot colours also involved in the print image. If you want to simulate this in Photoshop, even a very experienced user will be busy for two to three hours, a less experienced user for a whole day. In Spectraproof it only takes a minute.

Matthias Betz: That means you can simply load even such complex files with underprinting white and many spot colours into Spectraproof, can then assign such functions to the individual channels, and then get a clean view of it calculated?

Alexander Demmler: Correct. Spectraproof does this by integrating a RIP and generating separations first. The composite file that is loaded into Spectraproof is first broken down into the individual separations, and then Spectraproof works on these pixel layers.

Matthias Betz: Doesn’t this example also show for which target groups Spectraproof is best suited? Who are the users who are craving to use this softproofing software?

Alexander Demmler: The repro houses and reprographers, also the printers and their pre-press to have a look: Is the PDF separated correctly, where do we want to go, is the print in the softproof correct? Spectraproof can also be used perfectly on the press as a support for the printer, e.g. with the viewer. Today, printers often only have one hardcopy proof, and where the gold foil should be, a yellow or gold tone is simply printed. This is often better to show in a softproof, for simultaneous contrast and so on.

The marketing departments of major brands are also typical Spectraproof customers. And the different versions of Spectraproof can also be used in different ways: A Spectraproof customer with a light bonnet and hardware calibrated monitor, and he has reduced his preflight proofs by 80% in catalogue production. Such a catalogue is really boring, only 4C, but they used to proof almost every page. Now only the critical pages are hardcopy proofed and the less critical pages are screen proofed.

Matthias Betz: This customer has the Spectraproof system in the premium version with hood and standard light and the softproof screen as a complete package? Is that also on the printing machine?

Alexander Demmler: No, it’s in the advertising agency that produces the catalogues. Another client does fashion, and proofs every page with his client. But especially with catalogues, you could reduce the proofs with a softproof system like Spectraproof to the key visuals, which are important on paper, and the rest is done on the screen. In this way, 90 pages can be quickly saved in the proof for a 120-page catalogue. That saves money and is faster.

Matthias Betz: But the packaging industry is already the primary customer base, isn’t it?

Alexander Demmler: It depends on the licence. The Standard 4C licence is for those who don’t want to do anything with foil, spot colours and paper simulations, and the Professional licence is for those who need and want it all.

Matthias Betz: And the client then uses the viewer?

Alexander Demmler: Exactly. The customer plays the licence and can then display the jobs from the repro on his screen and sees what the repro sees on his screen. He can validate his screen and he can validate his job so that he is sure that he has seen 100% of what his repro has seen. He can add comments to the jobs and send the job back so that the repro can continue working on it. But the viewer cannot open and process its own PDF files and configure and change configurations. That’s the principle of hardcopy proofing, as Proof.de does: if you send a proof, the customer can’t change the proof, and that’s not what you want. And that’s exactly what you don’t want in the Spectraproof viewer. The customer should not be able to select a different ICC profile and then see a completely different softproof result in his softproof viewer. Exactly as in the classic paper proof.

Back to the paper: This is of course also a point, the paper simulation. Honestly, except for the classic proofs from the ISO standard, the proofs with strong paperwhite simulations often don’t really look good. GMG could also simulate a surbalin, i.e. a wavy structure in the proof, but the classic proof has a grey or beige tone in newspaper printing, i.e. a flat colour result. If the paper is structured, then this often does not work in the classic proof.

With Spectraproof you can scan this paper, save it, place it in a folder and then load it directly as a background instead of the paper white simulation from the ICC profile.

Matthias Betz: So if I have a calibrated scanner, I can simply use all kinds of papers as backgrounds in Spectraproof. And if I want to show this to my customer, he would also be able to display all these things with his viewer.

Alexander Demmler: Exactly. The Spectraproof full version generates a Spectraproof job and the scan is then packed into it. This is then sent as a job to the customer, who presses the button and can then see exactly what the repro has previously done with their data. It works like this: Everything is saved in the jobs, and on the viewer computer itself, only the screen profile of this computer is calculated, and the job is displayed perfectly. The whole process is very simple with the Viewer: the job with spot colours and process colours is calculated into the screen profile and that’s it.

Matthias Betz: What does a complete job calculation in Spectraproof look like?

Alexander Demmler: PDF with spot colours and process colours is calculated via a RIP in separate colour separations, then all colour information is collected, the colours are spectrally calculated for all colours, as desired with paper tone or without paper tone in the simulation. The mathematics of Spectraproof also starts like this: If the ICC profile contains a paper white simulation, then the Spectraproof engine first fetches this paper white tone, places it at the very bottom as the first level and spectrally multiplies all other levels above it. And that with opacity prediction!

Matthias Betz: What does that mean: opacity prediction?

Alexander Demmler: Different colours print differently together and behave differently in terms of their opacity. Now the opacities come into play: Ideally, the customer has printed colour ramps once against black, grey and white, and these were then measured and stored in the CXF. In the worst case, we only have one solid tone, and then an algorithm activates that performs voodoo and witchcraft. A crystal ball algorithm that predicts the opacities as likely as possible.

Matthias Betz: What is the most important feedback from customers about Spectraproof? Is this a new level of soft proofing?

Alexander Demmler: Some test customers say: We print 4-colour, we use densitometric measurements or, in case of doubt, classic proofs and we don’t need that. But there are also many customers who say: WOW, this is exactly what I always wanted. They are absolutely thrilled with Spectraproof. They have also shown it to their customers and they use it as well. Of course, a young software is often overrun with wishes, but the functionality of Spectraproof inspires most users.

Matthias Betz: Spectraproof runs on Windows and Mac, right? What else do you need to display really good softproofs?

Alexander Demmler: A reasonably fast computer and a hardware-calibratable monitor with a good colour gamut. And in the best case, a measuring device like the i1 Pro 2 or the MYIRO1, with which you can measure spot colours and the whiteness of printing paper. Or an i1 display. You only need the first two measuring devices if you want to measure spot colours or papers. If you only want to validate spot colours or the monitor, the Display Pro is the preferred instrument.

Matthias Betz: Thank you very much. I have now understood a lot more about soft proofing with Spectraproof. But perhaps once again as a final question: How can I be sure that what I see is really correct?

Alexander Demmler: Let’s focus on the paper analogy of the classic proof: When I set up a proofer, I make a linearisation and an ICC profile. This is exactly what happens when I set up a monitor. The hardware calibration is nothing other than the linearisation in the paper proof. The system sets the brightness to the right values and adjusts the RGB curves until it is neutral. And then an ICC profile is generated. You do the same thing when you set up a proofer. Then you create the workflow for the proof, which is exactly the configuration in Spectraproof. There is an output profile, a paper white simulation, a colour library for spot colours and much more. That means: Spectraproof has to be compared with a classic contract proof RIP.

A proofing service provider like you at Proof.de generates a paper proof, then takes the measuring device and measures the UGRA/Fogra media wedge. Sometimes you also use a spot colour media wedge, which also shows the spot colours. This is the job validation in Spectraproof. So you could also create a nice graphic: Above the Spectraproof, below the Proof, to show: SpectraProof does the same, but only on the screen. SpectraProof has the same parameters and the same control mechanisms.

There is now also a TIFF workflow for textile printers, for example, which work in sRGB TIFF.

Matthias Betz: Or soon in TextileRGB, Fogra58.

Alexander Demmler: Yes, exactly. The input doesn’t matter. The textile printers are pixel-based, so they can use Spectraproof, load the TIFF and see how it looks on different fabrics.

Laisser un commentaire

fr_FRFrançais