Gloss Differential on K3 Inkset

[John R Smith]

Folks

I have just moved to a pigment ink printer (Epson R2400) from HP dye-based printers, and have come up against the problem of gloss differential straightaway when printing glossy B/W prints. When you hold the print at an angle to the light, you get a solarised effect in the transition from ink to no ink in the highlight areas. How do you all deal with this? There is a thing called Highlight Point Shift in the software, but this seems to apply an overall light grey tone to the borders of the print as well as the image area, which looks horrible. Any help you can give would be much appreciated.

John

[Geoff Wittig]

It is what it is. With this printer and inkset, gloss differential and bronzing is a fact of life, one that is especially apparent in black & white prints. On matte fine art papers it has no such problems, but then you lose that great deep black.
For what it's worth, the Dmax this printer offers on semigloss/luster paper is so good that I think it's a fair trade off. If your print is mounted under glass and properly lit, the gloss differential will be hard to notice.

[PeterTinson]

John If you check borderless as well as the highlight shift this will put the slight amount of light light black over the whole of the paper including the borders.
As our eyes take the lightest shade as white (within reason) the slight grey will be invisable.
Peter

[dkeyes]

I don't leave anything to paper white, ie, no ink. I add ink to the highlights to help compensate.
Several methods I have used to some success are:
1. In curves, set output to 252. This adds a few % of ink evenly in highlights.
2. Pick a color you want to add to highlights like a light yellow or blue. I sample a common color near the highlights like in clouds for example. Make a separate layer and fill with that color, then select Darken for that layer. This adds the color only to the areas lighter than this color. Adjust lighter if needed so it looks like a smooth transition.
If you have a white border, make a mask so this doesn't affect that area.
- Doug

[Wayne Fox]

It is what it is. With this printer and inkset, gloss differential and bronzing is a fact of life, one that is especially apparent in black & white prints. On matte fine art papers it has no such problems, but then you lose that great deep black.
For what it's worth, the Dmax this printer offers on semigloss/luster paper is so good that I think it's a fair trade off. If your print is mounted under glass and properly lit, the gloss differential will be hard to notice.
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Interesting.  Bronzing is something I really don't notice with the K3 inkset.  

I don't worry too much about gloss differential either,  since everything I do ends up mounted behind glass.  Can't see it.

[picnic]

Interesting.  Bronzing is something I really don't notice with the K3 inkset. 

I don't worry too much about gloss differential either,  since everything I do ends up mounted behind glass.  Can't see it.
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I was thinking the same---no bronzing, much less GD than the 2200.  I do the same as above---adjust my highlights a bit.  Helps a lot.

I have noticed others are spraying as they did before---there's always that though I don't feel it is necessary.

Diane

[KenS]

Folks

...When you hold the print at an angle to the light, you get a solarised effect in the transition from ink to no ink in the highlight areas. ... Any help you can give would be much appreciated.

John
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On the Epson  (and some Kodak) papers that I use I do not see bronzing with K3 inks ( I have an Epson 7800), I believe what you referred to is gloss differential.

I have had very good success using Premier Art Print Shield to eliminate gloss differential in both B/W and Color prints on glossy paper.  The technique I use is to spray a single heavy coat moving across the print left to right, overshoot the print, move down but overlap, move right to left, overshoot again, etc. I hold the can about 6-8 inches away from the print.  Don't move too fast.  It is important to go passed the print on each pass, otherwise you may inadvertently spray to much on during the 'turn', causing a puddle or run'.  The print is held in an almost vertical position during this process.  That way the can stays close to vertical so the spray comes out smoothly.

If you do this right you will not get any puddles or runs.  The coating will dry evenly.  If you go too fast or hold the can too far away you will get a 'gritty' somewhat visible surface change on the glossy prints.

For large prints 16x20 or more, I use two cans at once, one in each hand.  I rarely ruin a print, but practice on a few scrap prints is a good idea.  The largest prints I've sprayed successfully are 24x32 inches.

It's a good idea to dust off the prints before spraying, place them under good light, and avoid a strong breeze (e.g. from a fan) that might kick up dust during the minute or less that they take for the initial drying.

The process really is pretty simple and risk-free once you get the hang of it.  It is even easier on luster papers.

Be sure to wear a good protective mask.  

One other point.  Gloss differential will vary depending on the light source... i.e. if it is diffuse (light from a bank of floods or a picture window) it will be a lot less noticeable than a directed point source.  You may want to take that into account, along with the suggestions above about placing it under glass (I never do).

[colinm]

For large prints 16x20 or more, I use two cans at once, one in each hand.  I rarely ruin a print, but practice on a few scrap prints is a good idea.  The largest prints I've sprayed successfully are 24x32 inches.
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Interesting; I've never heard of the two-fisted approach to spraying before.

How are you using each arm to get an even coat? Trying to visualize this, I keep coming up with ways that would seemingly create puddles.

[John R Smith]

Folks

thank you all very much for your input. You have to bear in mind that I am completely new to pigment printing, although I have spent a year and a half with HP dye ink printers, which have their own problems but not this one. I do have about thirty years darkroom experience in B/W and colour, so that is my point of reference. Still, I have had the 2400 for just a week and there is a lot to learn.

I tried most of the things you suggest, including the HPS, reducing highlights to 250 or less, and using a spray on the finished print. These have varying degrees of success, but the result is very paper dependant. None of them pleased me much. Bronzing I don't find to be much of a problem - it is there, but manifests itself as a very subtle gold sheen on the surface, which is actually not unpleasant, whereas the B9180 I tried had really bad pink bronzing on anything glossy.

The solution to the GD for the moment which is working fine for me is as follows - I figured that the problem is that the reflectivity of the ink is either more or less glossy than the paper, depending on the media, causing the differential reflection. So the thing to do is to match the reflectivity of the paper to the the ink. I find that Ilford Smooth Pearl is almost a perfect match, and the problem has gone away. Luckily, I quite like the Ilford paper  

John

[Panorama]

I have had very good success using Premier Art Print Shield to eliminate gloss differential in both B/W and Color prints on glossy paper.  The technique I use is to spray a single heavy coat moving across the print left to right, overshoot the print, move down but overlap, move right to left, overshoot again, etc. I hold the can about 6-8 inches away from the print.  Don't move too fast.  It is important to go passed the print on each pass, otherwise you may inadvertently spray to much on during the 'turn', causing a puddle or run'.  The print is held in an almost vertical position during this process.  That way the can stays close to vertical so the spray comes out smoothly.

Be sure to wear a good protective mask. 

This is interesting. As an artist, that also knows many other artists and professional conservators, the "vertical position" goes against everything I've ever been taught, have done, or have heard recommended. When varnishing oil paintings (and using a spray varnish), the paintings are always placed flat on a horizontal surface and the can held at least 12" away. I realize this is not an apple-to-apples comparison, but I'm wondering why you feel the vertical position is better. For art, it's been repeatedly proven that vertical placement leads to more runs, drips, problems etc. and it is far better to use several thin coats compared to one single coat.....

[Mussi_Spectraflow]

If your using the driver to print with make sure you use good profiles. I never really had any problems with gloss differential on the K3 inkset, unlike Ultrachrome, where the deep blacks looked like they were raised compared to the rest of the print. Bronzing was always the thing that bugged me and for RC papers I ended up coating them quite often. Using good profile with a few carefully chosen media should give you good results. I can second your choice of Ilford Smooth Pearl as a good media, although it's archival stability is somewhat in question. I think my favorite for K3 would be the Legion Pearl. Look for Epsons new Semi Matte 260 as a good choice when it starts to ship as well, although it may again only be offered in large rolls. If your doing a lot of printing a good photographic RIP Like Image Print may also help to reduce bronzing and gloss differential.

Julian Mussi