My experience is that the need for a glass carrier depends on the condition of the negative, the base material of the film, the position of the image on the roll, and the f-stop I use.
Kodak's "Estar thick base" tends to be pretty flat for me. Larger than 4x5, though, even that can sag. Acetate base films seem to be thinner and more subject to curling (especially 120 size).
I use f/11 when enlarging 120 and 4x5... and f/5.6 with 35mm.In my case most focus problems are caused by (mis-)alignment of the enlarger or de-centering of the enlarger lens. I don't know if quality control has improved since the early 1980's, but I recall a nicely-done article in Camera & Darkroom (??) about enlarger lenses. The most striking finding of the author was that a dismally high percentage of enlarger lenses, from all manufacturers, were decentered, so that the four corners of a projected image were not equally in focus. [I'm sorry I can't be more specific about the article, but I just moved into a new house, and my photo books and magazines --- along with my darkroom --- are still packed or otherwise in disarray.]
My first enlarger, a little Soviet 35mm enlarger-in-a-briefcase, used glass on the bottom of the carrier. It did a remarkably good job of keeping negatives flat. It was good enough, in fact, that the enlarger worked nicely in auto-focus mode. Of course, the lens was pretty rudimentary (3 or 4 elements, probably) so I had to stop down quite a bit for reasons of lens optics alone. Curling just wasn't an issue.
For my current enlarger I use a two-glass-plate 4x5 holder (anti- newton on top, regular on bottom) for almost everything, with a set of thin black masks to control flare and help center smaller negatives. An anti-static "gun" made for vinyl records, plus a little compressed air seems to control dust well enough that I rarely use my glassless carriers even when curling is not an issue.
MyronOn 18-Jun-08, at 10:33 AM, <C.Breukel@xxxxxxx> <C.Breukel@xxxxxxx> wrote:
Hi Ibrahim,For negatives upto 6*6 I use carriers with only one piece of glass, on top of the negative. Best is to have AN glass (Anti Newton rings glass). For 4*5 inch I use two glass plates, and keep them very clean. Dust can be a problem, but in my darkroom it is ok.Best, CorFrom: pure-silver-bounce@xxxxxxxxxxxxx [mailto:pure-silver-bounce@xxxxxxxxxxxxx ] On Behalf Of Ibrahim PamukSent: woensdag 18 juni 2008 14:25 To: pure-silver@xxxxxxxxxxxxx Subject: [pure-silver] Glassless carier Hi,I am using a glassless carrier for a long time. I know that due to some curling I cannot get everywhere on focus. What I do is to stepdown to get most to focus. Alternative is to use glass carier, but in this case the dust, etc is a huge problem Am I doing rit? Any comments to me?regards Ibrahim Pamuk
