I have some scientifics works that goes beyond what we usually need in classical photography prints. I mean each print will be analyzed on an optical measurement system measuring resolution, contrast, noise level, etc…
Here is what I am looking for :
- The best details possible (usage : resolution measurement).
- The smoother print possible (usage : noise measurement).
To push this to a scientific level (measured with macro camera) I would like to get more informations about some of theses points :
- Ink limiting seems to decrease graininess (less noise), resulting in a smoother print but what are the drawbacks of too much limiting ? Less dmax maybe ?
- Is there any link between ink limiting and print resolution ? (Actually printing in uni-directionnal, 2 880 DPI, 720DPI file (vectoriel, is there a better file to prepare ?).
- Does changing the dithering method can give better (or worse) results about resolution and smoothness ?
I’m conscious that all this stuff is very geeky, I’m looking to go at the deepest level we can to achieve the best result possible with the system. I know that all of this do not matter for photography but at the scientific level, 5% better is 5% better.
Any help would be greatly appreciate for digging into this.
Thanks a lot !
Frankie, you need Ergosoft rip that does intelligent dot placement in multi-channel mode. QuadtoneRIP dithers each channel but is not aware of the others so dots get doubled up randomly. Ergosoft does not do that. It places dots of 1 channel between dots of another channel. You also need to mix your own inks to create dead-neutral K7. So pro warm, pro cool, and Epson VLM tint mix. You also need the Epson P900 printer which has a 2 picoliter drop. It works with Piezography in the EU.
Print on a matte surface baryta paper . . . I think Canson sells this type of thing now. It used to be Harmon Matte Baryta . . . similar to the old Ilford Matte silver paper . . .
Get all this and you can do proper scientific printing.
Thanks for your answer on all this but I can’t change all my print system right now for this kind of works (I should have been more specific about this) (also I need to print 44") so I’m trying to do “the best” with what I already have (9900 with dual K5 Piezo Pro + QTR/Print Tool).
Can you help me about these questions to use what I already have to the fullest ?
Any help about my questions ?
You have my opinions on the matter Frankie . . .
Changing all the hardware and the software I’m actually using yes, sure it will be better but unfortunately I can’t (at least for now) and I’m sure you can understand it.
That’s why I was asking questions to improve what I can do with the hardware and software I already have because I know you have a lot more experiences and knowledge than me about theses geeky questions.
I would recommend getting some epson premium glossy 250 (44”). You will be doing all of the following adjustments on this paper. First thing is doing a 1 meter adjust in service mode. It’s called “band feed adjustment” in the service manual I think. The paper feed is central to everything. After that, You’ll then need to do a physical alignment adjustment / verification, for this, See “PF head slant” and “CR head slant” in the service manual. After that, you need to do a manual head alignment in regular user mode. Evaluate with a loupe very carefully and make sure you get it right. Then you’ll want to make a custom paper type in printer and make sure head height and media type and fine paper feed adjust are all as optimal as possible. Finally, choosing the best possible starting curve and getting extremely good readings while you’re linearizing is crucial to ameliorate as much noise as possible. For max resolution I would recommend a paper like pictorico high gloss white film or canson high gloss rc. The paper walker recommended will be very good too.
If you need further assistance I can help on the phone or zoom at an hourly rate
Thanks for your help on this topic. All the settings that you mentionned are already on point on my printer. My concerns are more about the questions I wrote above (ink charge, resolution, dithering, etc…)
About the paper, my client already chose one, mostly based on surface reflections, smoothness, sharpness and OBA.
Well, you could always double check those things, as they can shift over time. Otherwise, there really isn’t anything else I can think to do other than ensure that the starting curve is as well suited to the paper as possible, and that you get very good readings with an automated Spectro. It’s almost impossible to get perfect readings with an i1 pro. Use an isis or a dtp 70 or some such, or higher someone who has one to take your readings. Other than that, I really can’t think of anything besides changing software. If youve already fine tuned every aspect of your printer, I’m curious what else you thought might be suggested?
I was thinking more about the following aspects :
- Ink limiting : Limiting ink results in less noise (so better S/N ratio) but I don’t know the real drawbacks.
- Print resolution, as it is a vector file, I can make it bigger than 720 DPI if needed. Question is : How far can we go ? Will it be better or worse to increase file resolution, to what extend ?
- Dithering : does changing the dithering method will affect resolution (sharpness), or noise (smoothness), if so, is there any benefits to one or an other dithering method for what I’m looking for ? I don’t know much about the way dithering works.
Well, these things are pretty easy to test. There’s only like 3 dither methods and 2 viable printhead resolutions. Walker has put a lot of time into the starting curves, I’m sure it’s probably as good as it gets if it’s the exact paper you’re using. If not, then find the closest one and make a linearization. That will make it pretty much perfect, it’s just very important in terms of tonal smoothness and noise to get perfect spectro reading with an automated reader.