glassless vs glass negative carriers

[ronald moravec]

Interesting conclusions. I find at least a one sided glass necessary for 35mm. If one were to reflect a straight line on the emulsion side, you can see how it curves. Prints also show corner deterioration.

I can find no reason for a glass carrier for 4x5 as the film lies flat in a carrier or out. I have two 4x5 Omega glass carriers and two without glass. Grain seems to be sharp right into the corners with or without in 16x20.

I made a one side glass carrier for Omega 4x5 machines for when I print 35mm from them. I filed out a reg 35 carrier to accept an anti-newton ring slide cover glass. The regular glass ones have a locating pin right in the center so you can`t run a film strip straight thru. I got tired of putting it thru crooked and then putting the carrier in the machine cocked 30 degrees.

[Will Strain]

The film you use affects how much you can get away with a glassless carrier. My Tmax has a fairly thick base, and doesn't flex as much as tech-pan, which was exceedingly thin...

just one more variable I suppose.

I used the bessler "neg-a-scratch" (thanks for that one Paul...) for several years... not perfect, but pretty good.

[Jerry Cunningham]

Thanks for all the thoughts. I am using a Beseler 45 MCRX. I use a cold light and mostly Tmax film. I just found a used glass carrier and I think it will fit my unit. If so, I will run somest simple tests.
Again thanks,
jerry

[Brian Ellis]

John Sexton must not have read Barry Thornton's book because he doesn't use a glass carrier and he makes pretty nice prints. I have both types of Beseler carriers and I've used both types in my Beseler MXT, there is no discernable difference in the prints. The only time you need a glass carrier with normal 4x5 film is when you're using a head that gets so hot the negatives "pop" with long exposures. Otherwise you're just spending unnecessary time keeping glass clean. 8x10 is perhaps a different matter, I don't know because I've only contact printed 8x10.

[Gene Crumpler]

My brief work with 4x5, I don't use a glass carrier with my Omega D2.

I have an intense light source, 250w with condensers, so I can stop down to f22 and still get 30 second exposures when printing 16x20's. No need for glass for stiff 4x5 negatives.

6x7's need glass because of the thin base of most 120 films.

[Tony Karnezis]

There's obviously disagreement whether you need a glass carrier. Certainly a neg would be as flat or flatter with it, so what are the disadvantages of a glass carrier that would make you avoid using one?

[Ross Chambers]

I'm still pondering Barry Thornton's idea of one sheet of glass on top only. I would have thought that to exercise the principle two sheets, one top and one below would be necessary?

While on "Edge of Darkness": is the unnamed British made enlarger to which he refers and which does not employ glass neg carriers the Devere?

Regards - Ross

[Armin Seeholzer]

Tony

there are many disadvantiges from a glass carrier. First is 4 more parts for collecting dust and dirth! Loosing sharpness true the anti newton glass!!!!!!
My 150 m Rodagon is sharpest at f 8-11 so if the neg is just hanging down in the middle a tiny bit f 11 will solve it, never had any troubles re unsharp negs.
The german sharpness guru Herr Ludwig from Gigabitfilm recomands to us no glass carrier or only one glass on the downside without anti newton glass!
For 8x10 best would be a horizontal enlarger!

[paulr]

comments and a question:

--one of the issues with neg flatness is the neg's tendency to buckle under the heat of the lamp. this is more significant if you're using a condenser of color head.

--if you do use a glassless carrier, you can use tape at all the corners to pull the neg tight. not perfect, but it helps.

--i'm not surprised by the comments on 35mm looking better with glass. i've always done 35 without, but it's obvious to me that the film isn't flat. it retains a good bit of that original curve, even when squeezed by the holder. might vary from film to film.

--question on Armin's point: has anyone compared a print made with anti-newton glass to one made with regular glass, everything else the same? i'm curious to know if there's really a noticeable difference. I always used anti-newt so i don't know.

[kev curry]

I'm still pondering Barry Thornton's idea of one sheet of glass on top only. I would have thought that to exercise the principle two sheets, one top and one below would be necessary?

While on "Edge of Darkness": is the unnamed British made enlarger to which he refers and which does not employ glass neg carriers the Devere?

egards - Ross

Ross I use a Devere 504 enlarger and the negative carrier is built to accept glass or metal inserts. Personaly I started using one piece of glass on top but for no reason other than, Barry Thornton said so.....never really thought much beyond that at the time!

Out of curiosity I just had a good look at the carrier to see whats what. In my case I can see that the glass on top acts to clamp the neg tightly all the way around its edge keeping it taut, so I think that this might effectively eliminates the possibility of the neg sagging and at the same time acting to shield it from any heat or upward buckle. When I removed the glass I notice that the neg (HP5+) visibly sags a little.

To quote Barry Thornton ''The tolerances of flatness at the carrier to project a sharp enlarged plane image are very fine , and no lens at any price can bring this non-flat negative into focus all over its surface simultaneously, no matter how much you stop down...''

That said I don't think Ill be contradicting John Sexton methods anytime soon.
I might use my next bout of curiosity to do some comparison prints with and without glass to see whats what.

kev