Questions & Answers
Does Caldera offer a backlit printing color management course?
Caldera offers Basic Color Management webinars (free for CalderaCare users). You can register to our online training from an active WorkSpace account.
Can backlit printing do G7?
G7 is a method to define gray balance: it can be used to profile backlit but nothing specific in the method concerning Backlit.
Is there an international standard for Backlit printing? For example, ISO?
There are no specific standards like ISO, but there are existing Fogra research (Dorin Pitigoi 2019).
I know it depends on the printer but what should the average or range ink limit be for a backlit profile?
Impossible to tell because it depends on the substrate, the inks, and the linearization settings. The ink limitation should be set up at the point where you can’t see any artefact or overinking effect on the print output.
Any recommendations regarding using D50 vs. D65 illuminants, and 2 vs. 10-degree observer angles for backlit specific profiles? (We use D65 LEDs, for your reference)
10-degree observer angle is meant for textile/fashion applications. Backlit printing is meant for display purposes. So, we would go for 2 degrees anyway. Of course, D65 illuminant is a smart choice as you use D65 LED.
The spectrophotometer provides spectral data, the importance is to understand for what light source the profile needs to be created. If the print is displayed in a D65 LED lightbox, then simply choose D65 as viewing conditions from CalderaRIP EasyMedia.
What should I consider when profiling acrylic materials?
It is important that the measurement aperture is chosen in accordance with the patch size. For backlit, it is important to keep in mind that straylight from the neighbor field plays a role in measuring. So, a good rule is a small measurement aperture and a big patch size for flat surface. For even higher accuracy it's also possible to use a bigger measurement aperture but then a really big patch size.
The LFP qb can measure material up to a maximum of 5mm thickness when doing backlit. So, if a 20mm thickness material must be printed for instance, it is recommended to look for the same material but with max. 5 mm thickness then create the profile there. See more details in Barbieri white paper.
Would the variable aperture function help with calibrating reverse prints on clear acrylic such as 3mm and 6mm?
It all depends on the resolution of the print. Acrylic usually has an even surface so a small aperture can be enough. However, because of the thickness of the material, it could be better to select a wider aperture. In any case, the wider the aperture, the wider the measurement area, so the better the spectral computation. Of course, when using large apertures, big patches (8mm) are required.
When using the light on the TotalColor, will it profile for a Night & Day look or only for a Night look?
It would be only for the Night look, since the Day look doesn’t require back-lighting.
Is latex printing more suitable for backlit visuals in general?
Not specifically. In general, Latex, Solvent or UV inks can all be used for backlit visuals. Each ink has its pros and cons. UV is quite popular for backlit, as it is possible to print more ink on the substrate and get a better contrast with back-lighting while delaying overinking issues.
I noticed a significant size difference between the file and the actual print.
CalderaRIP features a tool to avoid that. Use vertical/horizontal compensation in EasyMedia or from the print module. You can learn more about it by reading our dedicated article: Printing dimensions shifting unexpectedly on material.
I have a printer with an embedded spectrophotometer, can I use it for backlit media calibration?
No, only the Barbieri LFP spectrophotometers can perform measurements for backlit conditions. We do not recommend using the embedded devices in your printers.
I have a Barbieri LFP 5.3 with the backlit light source, can it be used to make backlit profiles?
Of course, just switch the spectrophotometer in "transmissive measurement" mode from EasyMedia, before measuring your targets.
Which transparent sample holder should be used to hold the targets when measuring with a TotalColor?
For this webinar, we have used the transparent sample holder which consists of two transparent sheets. The textile target can easily be slipped in between.
When using printers with the double strike mode (double inking), should the whole profiling be done with the targets printed in double inking?
Absolutely. During the calibration step, you must always honor the final printing conditions used in production. If double-inking is used in production, it should be used when creating the profile as well.
Which profile is better for textile?
Talking about output CMYK profiles, there is no such thing as a “better” profile. Each output profile must be made according to the printer/production variable. Speaking about input profiles (the one embedded in the files to print), unfortunately there are no standards in textile/wide format printing application with inkjet printers. Usually, our customers keep on using Fogra39 as input profile, but it really depends on the media used. When it comes to RGB profiling (CalderaRIP RGB workflow), we see a lot of customers using a sRGB color profile as the input profile, which is not a very good choice. This is why FOGRA research is ongoing to have a proper input profile for textile in RGB.