Blocked- Clipped Shadows

[davidh202]

  I have been tearing my hair out trying to print a canvas for a client, that keeps blocking in the shadows despite looking ok on screen. Did a search and discovered that this is not at all uncommon, and Schewes answer on this thread sounds like a winner.


http://www.luminous-landscape.com/forum/index.php?topic=50712.msg419056#msg419056
  I was headed in the right direction brightening the shadows with the adjustment brush in ACR, but felt I was lightening the dark areas too much.
I guess it will be necessary to prevent the blacks from blocking that I have been getting on the test prints.
Can't wait to try this on the file on Monday!

Thanks Jeff!
David

[pfigen]

David - what printer, what canvas and where did the profile for the canvas come from? While most inkjet printers will print anything below about 10 RGB as black with no detail, matte canvas sometimes pushes that up to around 15 or so, but it really depends on the printer, media and profile. What are the RGB values that are clipping on your print?

Also, are you printing from LR or Ps and if Ps, what version, and what OS version? If you're on a Mac you could be hitting the wonderful dark print bug as well.

I've been printing for the last week on Epson Exhibition Matte canvas with profiles I made for that on a 9900 Epson, and on an image testing the profile, I can see a tonal jump going up from 10,10,10 RGB but everything below that is crushed. You may need to move your RGB black point into the 15-20 range in order to maintain the detail you're looking for. And if your blacks have a lot of dark color in them, that will only exacerbate the problem. You'll have to both lighten and desaturate in order to address the issue.

[bill t.]

Sounds like a case of bad print profiles.  When you print a gray scale you should be able to see the difference difference between rgb 24:24:24 and rgb 16:16:16, but not so much below that.  IMHO almost without exception manufacturer's canvas profiles are too aggressive in the dark ranges.

But even so, on canvas and all matte media you need a lot of separation in the shadows.

Along the lines of what Schewe was talking about, Tony Kuyper has some excellent luminosity-based actions that create masked curves layers that very selectively target specific ranges of image brightness, and there are a 3 or 4 actions for the dark areas alone.  Very useful for fishing detail out of those shadows.

The use of luminosity can sometimes paint you into a corner.  For instance rubber stamp modifications with an existing luminosity mask can sometimes create ghost images of the stuff you are trying to remove.  You have to remember to regenerate the masks when you change the image.

[bill t.]

Without seeing the original it's hard to know what I personally would do.

But here's what I got by creating a Curves Layer, and then clicking the Select->Color Range tool on the pink X with a Fuzziness of 44.  You can see the wild curves layer.

Problem is, that painting is very dark!  Would be nice to have layered exposure brackets of the original, pick out dark detail from an exposure where the shadow areas are brighter, then make them darker with a masked curves layer.  That would give you lots of detail and gradation in the dark areas.

Note you can paint out certain areas on the mask if you need to.

The contrast is still a little non-vibrant to print well as a Fine Art Reproduction Print, more work is needed to reach Awesome.

And just as a thought...if you could find a more open original of this piece, you possibly substitute dark areas with more detail for the ones you got.

[craigwashburn]

  I have been tearing my hair out trying to print a canvas for a client, that keeps blocking in the shadows despite looking ok on screen. Did a search and discovered that this is not at all uncommon, and Schewes answer on this thread sounds like a winner.


http://www.luminous-landscape.com/forum/index.php?topic=50712.msg419056#msg419056
  I was headed in the right direction brightening the shadows with the adjustment brush in ACR, but felt I was lightening the dark areas too much.
I guess it will be necessary to prevent the blacks from blocking that I have been getting on the test prints.
Can't wait to try this on the file on Monday!

Thanks Jeff!
David

Could be dot gain (physical and optical)... I'm not aware of profiling solutions that take this into account.  I'm not a canvas printer, but its common on matte.  My usual solution is to just raise up the shadows curve a slight amount, and make test prints and test strips of problematic areas until it looks acceptable.  It's not fast, but trying to find an easy fix that doesn't exist is even slower   Also, I'd say for one type of paper or media, once you find a good curve, it works 90% of the time with other images with few modifications.

[ippolitois]

I would check out Imageprint and see if that helps. I know with my 4000 I had the exact same issues on Luster paper. I got custom profiles made, bought the Spyder system to make custom profiles, all with the same results. Then I tried IP and all my problems vanished. Now I get full gradations across the blacks. Download the trial version and see if that helps. It's expensive but I wish I had known about it before I did all of the above and maybe I might still have some hair left. I guess I became converted.

Hope this helps.

Paul

[ippolitois]

I would use the black point compensation slider to see if you could add a little punch. Also, check which profile you're using when you're printing.  Check if you're using PK or MK profiles. I'm not a canvas guy, so I can't answer which ink you have to use. Check with IP and see what they advise.

Good luck.

Paul