Paper sharpness

[Eric Rose]

I hope this hasn't been beat to death already, but I was wondering which B&W paper is considered the "sharpest" when used with an enlarger. Not talking about contact printing or litho stuff here, just what paper appears to be the sharpest. I would suppose edge effect etc might play into this, but I'm not sure. It seems silly to spend all this time, money and effort on getting razor sharp images on the neg and then getting less than optimal sharpness in the print. Again not counting the enlarging lens, shaking enlarger and such.

Thanks for your help.

Eric

[David A. Goldfarb]

There's this theory that graded papers are sharper than VC papers. It may be true, but it could depend on various factors other than the paper, like the light source and filtration.

My theory on this is that VC papers have a wider spectral response than graded papers (otherwise the filtration wouldn't work), so they will show up chromatic aberration in the lens more than graded papers, depending on the filtration, the lens, and the light source. If you use an apochromatic lens or a narrower band light source or a strong monochromatic filter, you shouldn't have a serious problem with chromatic aberration, so you might not notice a difference under those circumstances.

[Ed Sukach]

</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (David A. Goldfarb @ Feb 5 2003, 02:19 PM)</td></tr><tr><td id='QUOTE'>
My theory on this is that VC papers have a wider spectral response than graded papers (otherwise the filtration wouldn&#39;t work), so they will show up chromatic aberration in the lens more than graded papers, depending on the filtration, the lens, and the light source.&nbsp; If you use an apochromatic lens or a narrower band light source or a strong monochromatic filter, you shouldn&#39;t have a serious problem with chromatic aberration, so you might not notice a difference under those circumstances.</td></tr></table><span class='postcolor'>
Chromatic abberation as an error in a lens system affects black and white media nearly equally as severly as color media.

The Spectral sensitivity of "Graded" (non-variable contrast) paper is not restricted to a narrow spectral band ... and few enlarger light sources (actually, none that I know of ) are to any great degree monochromatic. Chromatic abberation is caused by a lens design that focuses different wavelengths of light to converge to differing points ... and the worst case of that I ever encountered was in a Kodak Contour Projector - where the edge of a silhoette projected to the exteremes of its 30" screen were red on one side and blue on the other. Another Comparator manufacturer (Jones and Lamson) offered a monochromatic light source - a mercury vapor lamp - to avoid just that effect.

Enlarging lenses -- every one that I&#39;ve ever been in contact with - seem to have *very* little chromatic abberation - as a design criteria.


a defect

[SteveGangi]

Taking a different tack, to at least give the impression of greater sharpness, you probably would want to use a glossy paper. Apparently, any sort of texture will look a bit softer (but for portraits that would be good). The downside is that glossies have an "issue" with glare or reflections when viewed. To give the standard non-answer, our eyes can only resolve so far and anything more is gilding the lily. To further confuse things, higher contrast and colder tone can sometimes make a print look sharper, at least to some people.

[lee]

I have always used glossy paper because I just like the way it looks. I dry prints on fiberglass screens and they then have lost some of the "glossy". I am always amazed how good images dried that way look when matted and placed behing glass. It might just be personal preferance.

lee&#092;c

[Thilo Schmid]

Eric,

sharpness is often a synonym for “detail contrast”. Sharpness is more often related to paper grades than to paper quality aspects. However, the surfaces of the paper and the viewing conditions (e.g. glass frames) have an impact on visual contrast, too. All modern papers have a resolution power far beyond what the lens will deliver.

[Donald Miller]

I know that this thread started with the caveat of no litho. But if one is attempting to gain the greatest impression of sharpness in a print then unsharp masking procedures are a definite boon to the impression of sharpness.

There are two factors involved with this impression of sharpness. The first is that there are edge effects that come into play. The second factor is that by using an unsharp mask the overall contrast of the camera negative is reduced. This reduction of the contrast level in the camera negative is offset by using a higher grade paper (either VC or graded paper). This increase in paper contrast brings into effect greater local contrast. This greater local contrast then brings about an impression of much greater sharpness into the print.

The procedure of unsharp masking is fairly simple and straightforward, as far as masking procedures are concerned. All that is required is some really inexpensive litho film and diffusion material.

Insofar as paper sharpness in and of itself, I think that in my experience, the effects of spectral diffusion are non apparent. One can not create any portion of the visual spectrum that does not already exist. In other words you can not create UV from either the visual or the IR spectrum. Todays papers have very well defined response sensitivities. So aside from possible flare (which is another matter in and of itself), it would seem that papers will only respond to the portion of the visual spectrum to which they are sensitive.

[Eric Rose]

Do they publish lines per mm ratings for paper?

[Donald Miller]

While I can not speak to all papers, I have never encountered a published criteria by any paper manufacturer that addressed "lines per mm". Most of the technical publications related to a given paper address matters such as spectral sensitivity, paper speed, and characteristic curves. I think that the resolving power of the paper is actually a stronger link then some of the factors contributing to the image such as lenses-both taking and enlarging, film and developer choice, and other factors such as flare. It is the last link in the chain and while an important link, every other factor which could be detrimental to the image prior to the printing is amplified in the printing process.

[Eric Rose]

I have emailed Ilford and asked them if they have any data they can share with us on the "sharpness" of their papers. If and when they reply I will share it with the group. I won&#39;t hold my breath however.