Inkjet RIP question

[Teh_Bm]

Is there a software inkjet RIP on the market that can emulate classic offset printing screens and separations on inkjet printer?

Like, to print black dots at angle of 45 degrees, same for yellow and cyan and magenta. Not to print diffusion dithered dots but real halftone screens. I know that inkjet resolution is lower than CTP of film device, but even lower resolution will do for me.

Im looking for such sotware for any platform but Id prefer to find Windows version.

Can you point me to URL of the company that sells such software RIP processor? (I have Epson Stylus Photo 1200).


thank you

tehBM

[JackBingham]

I assume this is because you are working with a designer who just has to see dots?

[AndrewRodney]

There are some very high end RIP's that can simulate a halftone dot but I don't know of any that would support the Epson or for that matter any (?) of the desktop ink jet printers. You'd be better off asking this question on the ColorSync user list. There are a few RIPs that can do this (Black Magic is one that comes to mind).

Frankly, this shouldn't be an issue for you but rather the people that will ultimately make a contract proof from either the electronic file going direct to press (those proffers simulate the dot pattern) or a true laminated contract proof (again they simulate the dot pattern). What you need (and can do) is use the Epson to simulate the COLOR but not the actual dot pattern prior to having a contract proof made.

[Teh_Bm]

>> Do you have a good (Better custom) ICC profile for the offset press? If not, how can it match?

I have offset printer custom ICC profile which I use in photoshop to make separation from RGB to CMYK. They made the profile. Additionally, that is one of the most accurate offset nearby. At least they have that reputation.

>> In order to cross render to an Epson (or any printer), you need a profile for the printer and a profile for the device you are trying to proof on that Epson. So you need a good CMYK profile for the final piece. You need to do your RGB to CMYK conversion for this process. Then depending on what driver you'll be using to the Epson, you need to do a CMYK to Epson conversion (CMYK to RGB if you are using the Epson driver since Quickdraw and GDI printers can't deal with CMYK data).

I have Profile for offset printer and I made the profile for my Epson printer using Eye One Match's printer profiling.

Anyway, when I calibrate monitor and printer using Eye One ... then what I see on monitor IS almost equal what I get on inkjet printer BUT differs from what I get on offset.
Bad side is that offset printers colors are the correct ones.
I do convert images for specific process, using custom inkjet profile for my inkjet printer and using custom offset printer profile.

>> I'm not following you here. deltaE is only a measure of difference between to spectral readings. You've got a measurement of the press but what are you comparing that to in order to get this deltaE reading?

OK, lets say we got color sample on the computer which i subbmited to my offset printer as the bacground on the page.
Color Sample = C100 M80 Y0 K0 (Euroscale coated v2) = L28 a13 b-53

Off paper measured values using SpecrtoEye: we get Lab color I cant remember exact value, but we can give it some imaginary value which doesnt matter atm.

That sample color Lab values when compared to off paper measured Lab values differ for dE 1.8 which is acceptable.

But that printed color differs from one I can see on my screen, significantly. Which makes Eye One monitor profile inaccurate, for quite alot. Since that color got printed rather dark, color on my screen is rather light compared to it should be.

But thats not right. Offset printer got correct colors. They really did. I tried to make output using MatchPrint elsewhere and Matchprint is almost exact match of what offset printer gave me. Even SpectroEye shows offset printed colors are correct.

I tried to profile my monitor using EyeOne over 100 times so far. I always get the same. Monitor image is much lighter than layouts are.

BUT If I print that same image and color background using my inkjet printer thru ICC made by my Eye One, I get a perfect match to what I see on screen. That makes my total calibration of inkjet and monitor inaccurate. I suspected Eye One device at first, but Eye One diagnostics says everything is OK.


>> Sure. What makes you say the paper reading in Share is off?

I have printed color we mentioned above: C100 M80 Y0 K0 (Euroscale Coated v2)

My Eye-One measurement of offset printed material gives Lab values which converted thru (Euroscale Coated v2) gives me value which has Yellow and blacK in it.. something like C89 M70 Y13 K2

Thats the same Eye One I use to calibrate my monitor.. which gives me inaccurate profile and monitor display which is too light compared to what I get on the offset output.


Thnx for all this Andrew. Im trying really hard to describe you whats going on here.


tehBM

[Teh_Bm]

My offset printer made custom ICC profile for me, but their (offset printers) main tech guy showed me that profile is -almost- a perfect 3D color space shape twin of (Euroscale Coated v2).

Thats why Im using Euroscale Coated v2 as reference here in my post above.

tehBM
p.s. Color I submitted was C100 M80 Y0 K0 - got by reading value from PDF file using PitStop and inside my working document in PhotoShop, which were later output to CtP, and printed then measured using SpectroEye giving dE 1.8

[ January 18, 2003: Message edited by: tehBM ]

[AndrewRodney]

>I have offset printer custom ICC profile which I use in photoshop to make separation from RGB to CMYK. They made the profile. Additionally, that is one of the most accurate offset nearby. At least they have that reputation.

Ok, so how is the output (forget the display) when you take a known RGB file in a known colorspace and convert from RGB to CMYK? Is the output OK but NOT match the display?

>I have Profile for offset printer and I made the profile for my Epson printer using Eye One Match's printer profiling.

At this time, let?s forget the Epson because you have three devices (Epson, Offset/Contract Proof and Display). Somewhere there is a problem in the chain and you have to figure out where it is. It could be the press profile, it could be the display profile or it could be the Epson profile. In fact, it could be the preview portion of either the Epson or Press profile (output is fine, preview is off).

>Anyway, when I calibrate monitor and printer using Eye One ... then what I see on monitor IS almost equal what I get on inkjet printer BUT differs from what I get >on offset. Bad side is that offset printers colors are the correct ones.

How do you know the offset is correct?
The Epson isn't going to match the press unless you profile the Epson and then use that to convert the CMYK file going to the Press to RGB for the Epson (using a Absoulte Colorimetic intent). You're not just sending the CMYK press file to the Epson are you? That will never work and never match anything.

>But that printed color differs from one I can see on my screen, significantly. Which makes Eye One monitor profile inaccurate, for quite alot. Since that color got >printed rather dark, color on my screen is rather light compared to it should be.

But the print to screen matching with the Epson is OK? So it could be the preview portion of the profile you got is hosed or you?re display profile is bad and you?re just lucky with the Epson.

>I tried to profile my monitor using EyeOne over 100 times so far. I always get the same. Monitor image is much lighter than layouts are.

But you?re OK with the Epson when CMYK doesn't enter the picture?

>BUT If I print that same image and color background using my inkjet printer thru ICC made by my Eye One, I get a perfect match to what I see on screen. That >makes my total calibration of inkjet and monitor inaccurate. I suspected Eye One device at first, but Eye One diagnostics says everything is OK.

To print to the Epson you?re doing a CMYK to RGB conversion (RGB profile the one you made)?

>Thats the same Eye One I use to calibrate my monitor.. which gives me inaccurate profile and monitor display which is too light compared to what I get on the offset output.

OR the preview portion of the output profile is hosed.

You?ve got to find out where the problem lies. If the display profile were bad, I?d think any print to screen matching would be bad. If the output profile were bad, the preview and the output would match but both would be bad. But it?s possible the CMYK output is fine and the display profile are fine but the preview portion of the CMYK profile is off so you get good output but bad previews. It?s hard to tell without more testing. Is the CMYK profile you got from the printer a custom ICC profile they built or just provided you some CMYK setting in Photoshop and saved out from there? Can you test print to screen matching with another device (how?s a straight RGB print to the Epson look when soft proofed with a custom RGB output profile you make)?

-->My offset printer made custom ICC profile for me, but their (offset printers) main tech guy showed me that profile is -almost- a perfect 3D color space shape twin of (Euroscale Coated v2).

That's meaningless at this point. IF you have a custom profile for the press, why would you even be looking at the Euroscale canned profile? That just complicates the issue.

[Teh_Bm]

>> Ok, so how is the output (forget the display) when you take a known RGB file in a known colorspace and convert from RGB to CMYK? Is the output OK but NOT match the display?

Yes, color values in the file and the output from the offset is correct. My monitor display is not correct.


>> In fact, it could be the preview portion of either the Epson or Press profile (output is fine, preview is off).

I figure that my monitor profile and my epson are off. Only two devices in whole process that are calibrated by my Eye One. Could it be that I got malufunctional Eye One device? It passes all self diagnostic tests though.

>> How do you know the offset is correct?
SpectroEye measurement shows it is. MatchPrint proof made at totally different place, (visually) tells me that offset print is ok.

>> The Epson isn't going to match the press unless you profile the Epson and then use that to convert the CMYK file going to the Press to RGB for the Epson (using a Absoulte Colorimetic intent). You're not just sending the CMYK press file to the Epson are you? That will never work and never match anything.

Epson is profiled, Im printing with PhotoShop using "Print With Preview". Image is RGB Adobe1998, Im using custom profile for my epson to print by setting it up as destination space in "Print with Preview" dialog. I think that Intent I use for print is Relative.

>> But the print to screen matching with the Epson is OK? So it could be the preview portion of the profile you got is hosed or you?re display profile is bad and you?re just lucky with the Epson.

My display profile is bad. I can manually tune the monitor to have it kinda correct. I just tweak the brightness of the monitor a bit and only then I get the correct picture that looks like offset print.
But thats not how EyeOne is supposed to work. I figure that my EyeOne is making profiles that display picture too light which makes pictures edited under that display profule too dark when printed.


>> But you?re OK with the Epson when CMYK doesn't enter the picture?

Yes, Epson gives me what I see on the monitor. Epson and Monitor profiles were made using same EyeOne Pro UVCut device.

CMYK output on offset print and matchprint is much darker.

>> To print to the Epson you?re doing a CMYK to RGB conversion (RGB profile the one you made)?

I have images saved with Adobe RGB 1998.
- When printing to Epson I convert image from Adobe RBG 1998 to my custom epson printer profile (Relative colorimetric).
- When printing to file for CMYK CtP I use custom printers ICC profile to separate images in PhotoShop. Adobe RGB 1998 -> CMYK profile I got from printer.

I still feel my Eye One is not measuring as it should.

>> Is the CMYK profile you got from the printer a custom ICC profile they built or just provided you some CMYK setting in Photoshop and saved out from there?

They say it is. Its ICC profile file. I beleve 'em its custom one because they usually send a new profile for every print job, regarding what paper someone is using, what dyes they have, etc.
Someone could think that they made incorrect profile for my exact printjob, but nope.. other process outputs like Matchprint make somewhere else shows they did ok.

>> Can you test print to screen matching with another device (how?s a straight RGB print to the Epson look when soft proofed with a custom RGB output profile you make)?

Im kinda lost here.
But if i got it right:
My Epson print matches my monitor. They are both profiled using same Eye One device. But their output is incorrect my printer and my monitor output is incorrect. It is. Must be. Because same files when outputted to MatchPrint, offset, later both measured with SpectroEye say that color numbers printed are correct. And that print doesnt match my monitor and Epson.

MatchPrint EQUALS Offset Print
My Monitor EQUALS My Epson

My outputs are NOT EQUAL to others outputs
All devices here are custom profiled.

I can make my monitor in CMYK soft-proof mode match CMYK output on paper. Just turn brightness down a bit. But again, then I manually adjusted monitor, and Eye One didnt implement it in the profile.

>> That's meaningless at this point. IF you have a custom profile for the press, why would you even be looking at the Euroscale canned profile? That just complicates the issue.

True. Forget Euroscale. Bad example from my side. I used it in previous post to show you that I can make euroscale to Lab conversion and that i know how that dE of 1.8 is calculated.
Altho Euroscale when looked as 3D and overlapped with profile I got from printer matches almost perfectly. Printer said I can easily use Euroscale without fear, but I asked em for custom profile which I got from em and used it at the end. Anyway, forget Euroscale, bad example.


tehBM