I sometimes use an orange filter. It will darken the sky more than yellow, less than red, and darkens foliage more than yellow. Adding two air/glass surfaces can reduce contrast slightly due to flare (flare from the subject itself and reflections between the filter and the front element of the lens, which are not affected by a hood, though one should always use a hood for other reasons), but orange generally increases contrast with B&W film, and reduces chromatic aberration by cutting out other wavelengths, so with B&W film, a strong monochromatic filter can actually increase resolution, depending on how well corrected the lens is.
Yes indeed. Older lenses were not always corrected across the spectrum, so what I stated previously could be wrong in such cases, specifically
when you're going back far enough that the lenses were not classified as "color (film) corrected" at all. Cutting off the tertiary wavelength (generally the blue) would improve performance even with black and white film. Such anomalies basically involve antique lenses, though some
of these have qualities much desired today, esp by large format contact printers.
I will echo the idea to check the filters for haze. I had a filter wallet that would fog the filters quickly. I think the plastic from the dividers outgassed and deposited on the filters. I switched wallets and the haze went away (after a cleaning). The haze certainly contributed to softer prints, but at least was so bad most of the time I noticed it just pulling out the filter.
I'm sure filters don't make an iota of difference to the image, but being a mad purist I never use them.
Yeah, Larry ... anything vinyl will outgas. Just look at the inside of a windshield above the vinyl dashboard. Plasticizers are voodoo to optics.
But multicoated glass resists even that kind of smudge better than plain glass because there is less to cling to.
Have you scrutinised the negative with a 4 to 8x loupé, or passed judgement on the sharpness by some other means e.g. holding neg up to light? A finished drum scan will give an overall impression on the definition of a lens and film, but all that is useless if an average lens, poor technique and even poorer scanning conspire to derail assessment.
I used an orange filter in my student days with Plus-X almost three decades ago and cannot recall any sharpness derangement issues from what was printed and exhibited in those days, even with the rather lowly standard of filters available way-back-when. Today we are fortunate to have so many exceptionally high quality filters available. B+W filters will not introduce a lack of sharpness, but resin filters will, and I have never stooped to use those things with any highly corrected lens. With all filters there is an increased risk of flare (exceptionally well controlled with today's multicoated filters) and, where more than one is in use (not recommended), ghosting and a loss of contrast. You could of course keep shooting without an orange filter e.g. try a red filter.
ditto but sharpness is like grain...
Originally Posted by BrianShaw
double shot of coffee just as likely
even an aspherical lens will be improved by a deep coloured filter if you are using slow film and heavy tripod mirror lockup...
Personally, I'd be looking elsewhere for the cause of your softness (after making sure the filters were clean, of course).
Good quality coated filters do indeed add more air-to-glass surfaces, but the effect is not only negligible, but no different than switching from a 4-element to an 8-element lens... While I will certainly grant the point to Drew and others that adding a filter to a given lens will affect image contrast in the shadows and maybe sharpness to an extent, I would imagine that there are more quality variances between the myriad of different taking lenses out there than would be introduced by adding a quality, coated filter.
And, there certainly should not be any difference in sharpness between shots taken with different color, but similar quality, filters.
Camera/subject movement, poor focus, poor scanning, etc. all seem to me to be more likely culprits.
FWIW, I've never heard anyone say anything like, "Oh, that 16x20 print is a bit unsharp; the photographer must have been using a filter!"
This whole topic can be definitely proven on an optical bench. But otherwise, it's common sense. I can even tell when wearing a smudged or
cheaper pair of reading glasses that something is off, compared to a recently cleaned good pair. How much does it matter? Just depends. I'm
of the school of thought that these little things tend to add up. A minor compromise here and there, and eventually it really does show in the
print. But not everyone has the same priorities. What I categorically deny is that filter quality is not a factor. Every filter manufacturer knows
that! I could same about the lens analogy above: If you've ever owned a multicoated dagor lens with only four air/glass interfaces no way
your eyeballs won't pop out (I know, hyperbole- but you get the point), compared to a plastmat, not to mention some zoom lens with sixteen
or seventeen separate elements. I really really does make a difference, and if everything else in the workflow follows suit, even the public
will quickly perceive something, even if they can't explain it. Happens all the time to me. But a misaligned enlarger, or cheapo lens on that,