glassless vs glass negative carriers

[Jerry Cunningham]

Sir:
I shoot 4x5 and 8x10. I use a glass carrier in the 8x10 and the prints seem fine. However, I use a glassless carrier in my 4x5. Am I losing some sharpness by using the glassless carrier due to flatness problems? Some up to date thoughts would be appreciated.
Jerry Cunningham

[paulr]

In my experience a glass carrier gives significantly sharper results with 4x5 than a glassless one. This will be especially true if your light source is a hot one.

The best film carrier I ever saw was for an HK horizontal 8x10 enlarger. It grabbed the film at the corners and pulled it tight as a drum. It gave the best of both worlds ... perfectly flat film, and no extra surfaces to attract dust. And it didn't leave a mark on the film.

Sadly, the carrier itself cost over $700. And the only similar thing I've seen for 4x5 is made by beseler, and isn't so well executed ... my friends who've used it call it the Neg-A-Scratch.

[John Cook]

After many moons of printing 4x5 negs without a glass carrier, I would think not. If you were losing sharpness you would most likely see it through the grain magnifier. And what a relief to be rid of the newton rings and extra surfaces to dust!

However, if you wish to "go for the gold", Beseler has a dandy 4x5 glassless carrier with little sharp barbs which stretch the negative tight as a drum when the lever is turned. Perhaps it could be modified to use with your enlarger. Mainly a matter of moving the locator studs on the bottom.

[Tony Karnezis]

In the words of Barry Thornton in his book, Edge of Darkness,"If you use a glassless negative carrier, you might just as well buy the cheapest enlarging lens you can find. You are simply throwing away the money and sharpness you paid for it in your enlarging lens, and also in your fine camera and expensive lenses you bought for it--often worth thousands of pounds." He shows a photo of 4x5 film bowing in a glassless negative carrier. The negative carriers that stretch the neg to hold it flat are obviously designed to do the same thing as a piece of glass. I don't know whether these are better than a glass neg carrier, but the choice between a regular glassless carrier and one with glass seems obvious based on Thornton's statement. As for me, what do I know. I only do contact prints. :)

[Graham Hughes]

Thornton's tendency to exaggerate is absolutely ludicrous in its scope, and his measurement techniques leave much to be desired; for example, he tried to compare a lightweight tripod to a heavyweight one by extending the column on the lightweight tripod.

That said, he occasionally has a point. 4x5 might be the point where glass carriers start becoming important--I've never heard of an 8x10 enlarger without one (although admittedly I am not real up on 8x10s).

[John D Gerndt]

Negative carriers vary a good deal in their build quality. It is not a good place to economize. I use the Bessler 4x5 with anti-newton glass and love almost every print. It is good, of course for all formats including doubling up negs from small and meduim formats. Newton rings still sometimes appear but I have always been able to shim them away. DO look at Barry Thornton's book and decide for yourself.

[Mark Sampson]

You don't say what kind of enlarger you have. Some glass carriers (like Omegas) can be found cheap used. Why don't you get, or make, a glass carrier and see if your prints look any sharper?

[paulr]

I second the vote for the beseler glass carrier. I believe it will fit some other enlargers too.

I modified mine to improve it. I had a machinist slightly enlarge the window and then bevel the edges of it to 45 degrees. Then I painted the edges black. This eliminates any edge effects from light reflecting onto the film from the sides of the carrier. Also makes it easier to print the full image. I also put foam weatherstripping inside the carrier all around the perimeter. This stops light leaks out the side, whih used to light up my whole darkroom.

All of this was done when I had a bit more free time, a darkroom, and no girlfriend.

[Oren Grad]

Whether you're losing sharpness will depend on the degree of enlargement, your working aperture, the amount of heat generated by your light source and the effectiveness of the cooling in your enlarger head, the film base you're working with, and probably other stuff too.

Using standard depth-of-field/depth-of-focus formulas, it's possible to calculate just how much "slop" you can get away with in the film plane.

I don't do much enlarging from 4x5, but when I do, they're usually small enlargements (<2x) and a glassless carrier is fine even for critical requirements.

[resummerfield]

For whatever reason, when I started using glass carriers I noted an improvement in my 4x5 work. Now I use a glass carrier for all sizes, including 35mm. And yes, I do note an improvement in my 35mm.

[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