Change in print tone


#1

We have an Epson 3880 that we have been using to make exhibit prints to replicate Jeffs Silver darkroom prints. We are using Selenium K7 inks but for and for shades 3-4-5 we are using Neutral.
This system has been working great for the last year and with no problems. Last week all of a sudden I started getting prints that don’t have the same highlights or density…they are close but something changed. I use the printer every week I always print a nozzle check before.

I tried to fix the problem by topping off all the ink carts and shaking them. I also ran 2 power cleanings as well as cleaned the capping station. When I fill the ink I am VERY careful to get the right ink in the correct position-I actually have written the position number on each bottle of ink.

My workflow has also stayed exactly the same. I always convert the image to a DOT Gain 20% space and print using QTR.

My thinking is that I mixed up the ink on accident but I really am very careful because I know the consequences of such a mistake!

Please Help!
Jeremy


#2

Hi Jeremy~

May I ask why you convert images to 20% dot gain for printing with Piezography and QTR? As per our manuals, the recommended Piezography and QTR workflow uses gamma 2.2, and our recommended workflow should always be followed for the best results.

There are three things main things that could cause the output shift you are experiencing:
A) if one or more cartridges were accidentally mis-filled with the wrong shade ink
B) if one or more carts were accidentally installed in the wrong position in the printer
C) settled pigment in the carts and ink lines can effect the output density and tone

To check these things to and fix your problem to resume printing:
[B]A)[/B] Think back to any cartridges that were refilled before this problem started. To check the ink in carts to determine if the ink is correct or wrong density, you will need some of the same ink tone/shade in original bottles to use as a base.
1. Get a piece of scrap matte or rag paper and some Q-tips
2. Shake the recently refilled cartridges and corresponding ink bottles to get pigment in suspension for full/accurate density
3. Let carts and bottles rest for a few moments for froth to settle, then dip the end of a clean Q-tip into the ink.
4. Wipe the wet Q-tip end evenly across the piece of paper. Label each ink smear to indicate the tone and shade, and cart or bottle.
5. Repeat step 4 with all suspected carts and the corresponding bottles, then dry the sheet of ink smears with a blower dryer on low heat for a few moments before evaluating the ink smears.
6. Examine and compare ink smears from carts vs. bottles. The tone and density should match between cart and bottle smears for the same tone/shade ink.
If you notice differences between the cart and bottle smears, that could indicate a mis-filled cart, and the cause if your output issues. If a cartridge has been mis-filled, then the best solution is to fill a fresh cartridge with correct ink, top off any other carts that are less than 1/2 full (always double checking each cart is filled and refilled with the correct ink shade). What I find helpful to avoid mis-filling headaches, is to mark the back of each cartridge with the Piezography ink shade that is to be used in that cart (so, the C cart is labeled “2”, LC is labeled “3”, M is labeled “4”, etc…), and always triple check the ink tone and shade of the bottle matches the cart I’m filling/refiling, before pouring ink (we have a large collection of printers, cartridge systems and full range of Piezography ink bottles that I use and maintain).

[B]B) [/B]You can easily check the shade placement by printing the ink separation image thru QTR’s calibration mode, as instructed here: http://www.inkjetmall.com/tech/content.php?144-Print-Ink-Separation-Image-thru-QTR-Calibration-Mode
Dry and examine the print. Each strip is labeled with the color position, and you can mark each row with 1-7 based on visual density (1= darkest/black, 7= lightest), then compare the shade placement/color position you printed to the ink shade placement chart to check if each shade is printing in the correct position.

[B]C)[/B] If there aren’t any noticeable differences between the bottle and cartridge ink smears, then we can assume your carts were filled with the correct ink, and move forward to find the cause (and solution) of your problem.
The next thing I think of is settled pigment, which can happen whenever pigment sits still, and occurs both in the cartridges and internal ink system of the printer. If you are dealing with settled pigment, this can be solved by removing and agitating all cartridges to ensure pigment in in suspension, and refill any carts that are less than 1/2 full. Reinstall the shaken carts and wait a few minutes for ink to settle and air to rise, then do 3 Power Clean Cycles to purge settled ink from the internal lines, and get in-suspension ink from the shaken/refilled carts flowing thru the lines and to the print head. Print a nozzle check to make sure all positions are fully printing, then print a test image to check your output.

If you continue having strange output after checking and confirming all the things listed above are correct, then another thing that could effect output density is particle build up in the dampers, which will essentially filter the ink more than the filter screen inside the dampers, and effect the output density. Also, change in the environment, especially temperature and humidity, can effect printer/ink output and how paper takes the ink. We follow Epson’s guidelines and recommend maintaining humidity levels between 40-60% for best function with the printer, inks and papers.

I hope this helps. Please let me know if you have questions, your results, or if there’s anything else I can help you with.

Best regards~ Dana :slight_smile:


#3

Hi Dana, I followed your recommendations on performing the tests. I can’t believe I have been printing in 20%Dot Gain…I guess I got screwed up but that’s how I have been doing it for a year and the prints have been wonderful! But now I will start using Gamma 2.2. for the next run of prints but I will have to go back and re-work each image in order to print in Gamma 2.2. I scan the film and apply Gamma 2.2 at that point but then I have been applying the wrong profile as I prep the file for printing. But for this problem I will stay in the 20% Dot gain since that’s what I have been doing and besides I am trying desperately to match what I have been printing for the exhibit. Like I said once these prints are finished then I am going to go back and start printing with the correct profile added to the files.

I did the q-tip swabs for all the positions strait from the bottles and then from the carts and after drying them my conclusion is that they match perfectly well- density and tone. I also printed QTR’s ink separation image and the shades are printing in the correct positions.

I did top off the carts and gently shook them and performed 2 power cleanings last week and the difference was still there.

Just to let you know again my problem is noticeable in the highlights-they are not brilliant and bright like before and it seems that there is less contrast overall.

The room environment has not changed. And I would like to know what you mean by particle build up in the dampers? Can I check and clean these screens?

To let you know a bit more- We are using Hahnemuhle Photo Rag Bright White with the K7-2880-HahnPhotoRagBrtW Profile- Matte ink printing at 2880dpi uni-directional.

This problem happened after topping off the ink carts after making a good print. We just purchased three new bottles of 220ml ink and they are square bottles unlike the other round bottles…but the ink shades are the same and I just oppend these and filled the low carts and did the ink level resetting procedure made a print and thats when the problem showed up.

Thanks for your help
Jeremy


#4

Thanks for the additional information Jeremy. Dampers are in-line ink filters, which collect particles over time and should be replaced every 1-3 years to maintain good flow and consistent output results. The ink has not changed at all, but we did recently switch to a new bottle design. It may be helpful for you to send me a printed nozzle check and 21 step strip to measure and heck your output linearization, this way I’ll be able to better tell the accuracy of your output to help find the best solution.
I will email you the 21 step image and printing instructions. Please let me know if you have questions or if there’s anything else I can help you with.

Best regards~ Dana :slight_smile:


#5

Hi Jeremy~

OK, I received your pack of printed samples, which is very helpful- thanks. I compared the individual ink shades of your printed Ink Separation image to numerous printouts I have collected over the years, though they are not the exact same paper, I don’t see any obvious density or tone differences between my samples and your printout. I also added to your ink smear sheet by applying smears of the same inks from my SEL and NU bottles, which are identical to your ink smears. Based on my experience with the range of Piezography inks and various Epson printer models, I feel your latest print tone is accurate for the SEL/NU ink combination you’re using and the previous warmer highlight output was tinted with yellow color staining, which appears to have now finally been purged. If you prefer the warmer highlights, then I recommend you add Warm-Neutral or Carbon shades 6 and/or 7 to your setup (CAR is the warmest Piezography ink tone).

I measured the 21 step strip you included to check your output linearization, which looks good in the highlights to mid-tones, but your 3/4 tones are slightly lighter than they should be (though I don’t see a noticeable visual difference when comparing your printed 21 step strip to my known good/linear 21 step printed from our 7880). Since you are using a combination of SEL and NU inks in your 3800, a custom curve specific to your exact printer, ink, paper and print settings will give you the best possible output for your specific setup. A custom curve will control density, the smoothness of tonal transitions and get you the best dMax for your combination, but will not effect the ink tone.
You can read more about and order custom Piezography curves for your specific printer, ink combination and papers here: http://shopping.netsuite.com/s.nl/c.362672/it.A/id.3682/.f?sc=15&category=-115#

Please let me know if you have questions, would like to have a custom curve made, or if there’s anything else I can help you with.
Best regards and happy printing~ Dana :slight_smile:


#6

Thanks Dana, we are interested in having a custom curve made…its something we should have done along time ago but we were so happy with our prints so we just put it off! I will review the instructions and have you do that for us. Thanks for all you help.

Jeremy


#7

Hi Jeremy~

Excellent, please let me know if you have questions.

Best regards~ Dana :slight_smile: