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Author Topic: Need more ink on backlit prints  (Read 487 times)

David Elmore

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Need more ink on backlit prints
« on: September 14, 2018, 05:57:00 PM »

I am using Lexjet Water-resistant satin cloth on my HP DesignJet Z3200 to make lamp shades.  See my site Photo-Lamps.com for examples.  The only way I have found to get enough ink for dark blacks and saturated colors from back-light is to print twice by rewinding the roll to the same starting point, with the problem that registration is not always good.  I have tried the HP profiles for HP Transparency Film and for other media such as canvas that take a lot of ink and they all give me much less backlit density for blacks than double the ink.  Surely there must be a way to modify the printer calibration, driver settings, Qimage settings, and/or ICC profiles to get double the ink.  Any ideas?

David

aaronchan

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Re: Need more ink on backlit prints
« Reply #1 on: September 15, 2018, 12:08:27 AM »

I am using Lexjet Water-resistant satin cloth on my HP DesignJet Z3200 to make lamp shades.  See my site Photo-Lamps.com for examples.  The only way I have found to get enough ink for dark blacks and saturated colors from back-light is to print twice by rewinding the roll to the same starting point, with the problem that registration is not always good.  I have tried the HP profiles for HP Transparency Film and for other media such as canvas that take a lot of ink and they all give me much less backlit density for blacks than double the ink.  Surely there must be a way to modify the printer calibration, driver settings, Qimage settings, and/or ICC profiles to get double the ink.  Any ideas?

David

You need a custom made icc profile for your backlit material.
Not many places does that but I think Andrew, aka DigitalDog has a Barbieri which does measure backlit materal.

Aaron

Ernst Dinkla

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Re: Need more ink on backlit prints
« Reply #2 on: September 15, 2018, 06:57:02 AM »

I am using Lexjet Water-resistant satin cloth on my HP DesignJet Z3200 to make lamp shades.  See my site Photo-Lamps.com for examples.  The only way I have found to get enough ink for dark blacks and saturated colors from back-light is to print twice by rewinding the roll to the same starting point, with the problem that registration is not always good.  I have tried the HP profiles for HP Transparency Film and for other media such as canvas that take a lot of ink and they all give me much less backlit density for blacks than double the ink.  Surely there must be a way to modify the printer calibration, driver settings, Qimage settings, and/or ICC profiles to get double the ink.  Any ideas?

David


Two sheets printed with one blurred, mounted on top of one another, blurred one reversed at the back. Lack of density is not cured by a custom profile, the media preset with the highest load of ink on the Z3200 does not cure it either.  Sure a custom profile could improve the two sheet sandwich color reproduction on top of that but at least you get the density. With the advantage that when the lamp is off the image still looks nice in reflected light, not too heavy then.  In printing large backlit posters this method has been widely used on offset printers but then by printing the backside of the poster sheet, register is easier on an offset printing machine than with fabrics on a roll inkjet printer. A flatbed inkjet printer + a temporary frame for the fabric might do it on one piece of fabric .

An idea; Heavy paper sheet printed with the reversed image, aligned to register tabs at the front of the printer. Add a mild spray glue on that sheet. Put the cloth on the sheet and print again with register tabs at the front of the machine. Reverse the cloth after drying that the image fits correctly on the already printed reversed paper image (lightbox underneath if needed), print the reversed image slightly blurred again, you could even vary the density to get less obvious alignment failures and enough total density.

Met vriendelijke groet, Ernst

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
March 2017 update, 750+ inkjet media white spectral plots
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arobinson7547

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Re: Need more ink on backlit prints
« Reply #3 on: September 17, 2018, 02:22:39 PM »

I don't think it's the amount of ink or the profile. I think it would be best to try/sample another/other materials until you see the density you are looking for.

With some Media/Ink combinations, it's just not there.

It's that whole getting blood out of a turnip thing.
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David Elmore

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Re: Need more ink on backlit prints
« Reply #4 on: September 17, 2018, 02:30:40 PM »

You need a custom made icc profile for your backlit material.
Not many places does that but I think Andrew, aka DigitalDog has a Barbieri which does measure backlit materal.

Aaron

I am not a super expert, but the issue for me is the amount of ink that is needed.  The HP printers are calibrated (separate from the ICC) to put down just enough ink to saturate with reflected light.  Anyway, I am choosing images for lamp shades that do not require accurate colors, such as NASA images of galaxies and earth clouds from space.  Some end up too light with the light on and some are good with the light on but too dark with it off.  Nothing I can do about this problem except to accept the fact that, when they are too bright with the light on, they provide more light to the room which is what they are for anyway.

Two sheets printed with one blurred, mounted on top of one another, blurred one reversed at the back. Lack of density is not cured by a custom profile, the media preset with the highest load of ink on the Z3200 does not cure it either.  Sure a custom profile could improve the two sheet sandwich color reproduction on top of that but at least you get the density. With the advantage that when the lamp is off the image still looks nice in reflected light, not too heavy then.  In printing large backlit posters this method has been widely used on offset printers but then by printing the backside of the poster sheet, register is easier on an offset printing machine than with fabrics on a roll inkjet printer. A flatbed inkjet printer + a temporary frame for the fabric might do it on one piece of fabric .

An idea; Heavy paper sheet printed with the reversed image, aligned to register tabs at the front of the printer. Add a mild spray glue on that sheet. Put the cloth on the sheet and print again with register tabs at the front of the machine. Reverse the cloth after drying that the image fits correctly on the already printed reversed paper image (lightbox underneath if needed), print the reversed image slightly blurred again, you could even vary the density to get less obvious alignment failures and enough total density.

Met vriendelijke groet, Ernst

Thank you both very much for your suggestions.  This one I don't really understand, and anyway it is too complicated for me. Sandwiching two media layers would not work well for a lamp.  Actually, we are getting pretty good with alignment for printing twice and the advantage over putting more ink down in one pass is that it gets a chance to dry between printings.

David

David Elmore

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Re: Need more ink on backlit prints
« Reply #5 on: September 17, 2018, 02:37:24 PM »

I don't think it's the amount of ink or the profile. I think it would be best to try/sample another/other materials until you see the density you are looking for.

With some Media/Ink combinations, it's just not there.

It's that whole getting blood out of a turnip thing.

The Lexget Water Resistant Satin Cloth works really great for this application.  It is thin and very strong.  As a cloth it bends well around the corners.  Images look really well backlit since it passes a diffused light.  I would not want a film material.  By printing twice we get deep blacks and bright whites.  I can't think of any reason a different medium would work better than this, but I am glad to try if anyone has suggestions.

David

nirpat89

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Re: Need more ink on backlit prints
« Reply #6 on: September 17, 2018, 03:10:44 PM »

I am using Lexjet Water-resistant satin cloth on my HP DesignJet Z3200 to make lamp shades.  See my site Photo-Lamps.com for examples.  The only way I have found to get enough ink for dark blacks and saturated colors from back-light is to print twice by rewinding the roll to the same starting point, with the problem that registration is not always good.  I have tried the HP profiles for HP Transparency Film and for other media such as canvas that take a lot of ink and they all give me much less backlit density for blacks than double the ink.  Surely there must be a way to modify the printer calibration, driver settings, Qimage settings, and/or ICC profiles to get double the ink.  Any ideas?

David

Couldn't you make prints on 2 separate papers and stack them (probably face-to-face) in much better registration than you are getting by printing twice on the same paper?

Regarding ink loading, on my HP B9180, there is an advanced setting that allows increasing ink volume from Light to Heavy (with Auto as default) independently from the profile.  Wonder if the Z3200 does not have the same.  The problem is if you go too heavy, then there is problem with ink pooling and resulting loss in sharpness and definition. 


:Niranjan.
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arobinson7547

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Re: Need more ink on backlit prints
« Reply #7 on: September 17, 2018, 03:41:02 PM »

how about trying to buy (or maybe even free) an old Rip. At least that will allow you to dial in 'exactly' where your maximum (lowest L*) is.

I'm all for using the Driver but a Rip lets you 'dump all the ink' (so to say) and then allows you to cut it back at an optimum setting. So at least you KNOW; here is the limits of a specific media/ink/printer combination.

Driver settings can sometimes be right on. But, there are times where you need to take the wheel.
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John Caldwell

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Re: Need more ink on backlit prints
« Reply #8 on: September 21, 2018, 08:29:08 PM »

The lamp's light source has everything to do with your apparent Dmax and dynamic range of the "projected" image. You've experimented with a range of source intensities probably.
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