Bump the contrast when enlarging

[ThePhotoDude]

I recently went to a trade show where there were several talks and demos going on.
I saw part of one and the discussion was around how contrast of a print drops the larger you print it.

Makes sense, and the speaker showed us how he uses Photoshop to increase the S curve (he had many presets) depending on how large he wanted to print.
It would add more punch to a large print than if you didn't do this.
Unfortunately time was short and I had to move on...

Any further thought on this? Are people doing this when enlarging? I print other peoples prints, and it would be extremly time consuming (and subjective opinion also) to do this to every enlargment, however it may be worth having a preset to sqeeze extra quality out of my output.

Qimage has 'Smart sharpen' option, is there one for contrast too?

Thanks

[walter.sk]

I recently went to a trade show where there were several talks and demos going on.
I saw part of one and the discussion was around how contrast of a print drops the larger you print it.

Makes sense, and the speaker showed us how he uses Photoshop to increase the S curve (he had many presets) depending on how large he wanted to print.
It would add more punch to a large print than if you didn't do this.
Unfortunately time was short and I had to move on...

Any further thought on this? Are people doing this when enlarging? I print other peoples prints, and it would be extremly time consuming (and subjective opinion also) to do this to every enlargment, however it may be worth having a preset to sqeeze extra quality out of my output.

Qimage has 'Smart sharpen' option, is there one for contrast too?

Thanks

I print from Qimage, often enlarging an image on the fly.  the easiest way I can see to change the contrast would be to set up an associated filter in Qimage and softproof the image in Qimage with the filter incorporated.  As you know, this would not change the file itself.

To be more obsessive about it you could print some test strips with different amounts of contrast.  You might even come up with a couple of flters to use as presets to be applied when you use that ink and paper printed at the sizes you're interested in.

[colinm]

It may have been John-Paul Caponigro who was presenting, in which case his general rule of thumb is to push the midtones 1 point darker for every doubling of the image area.

Printing your own stuff, this is easy no matter what method you use. You know how you hard proofed and what you did to the file.

Doing job printing, you're right that it becomes a little hairy and subjective—without knowing whether or not the client's already compensated for the optical effect, you can't tweak with any certainty.

[Dick Roadnight]

I saw part of one and the discussion was around how contrast of a print drops the larger you print it.

You need, or can appreciate, more detail in a larger print, and sharpening, increasing contrast or using Genuine Fractals can help.

A Local Contrast Enhancer looks as if it attempts do do what Phocus Clarify does very well on raw Hasselblad files.

[Ernst Dinkla]

opinion also) to do this to every enlargment, however it may be worth having a preset to sqeeze extra quality out of my output.

Qimage has 'Smart sharpen' option, is there one for contrast too?

Thanks

One may wonder how adequate the extrapolation routines were that the speaker used. And smart print sharpening. What data he started from and whether his smaller proof prints downsampled from too much data had an anti-aliasing filter passing or were treated with a similar curve to reduce contrast. Then there is the known gamma effect on extrapolation (small but exists) and the not so long ago here discussed frequency sharpening for different sizes. Caponigro's practical advice may have to do with this all but with different workflows that deal differemtly with the things above it will not be a rule for all. I like to rely on the 1:1 proof strip of Qimage till there is more known on this subject.



met vriendelijke groeten, Ernst Dinkla

Try: http://groups.yahoo.com/group/Wide_Inkjet_Printers/

[AFairley]

Can any of you more knowledgable types explain why this is so (contrast decreases with enlargement)?  I had always just assumed that while this applied to optical printing it was not the case with inkjet printing.

Thanks from a relative noob.