MF negative holder.

[fidget]

I am getting too many prints that have a soft or OOF area round the sides. I think that most of this is due to the 6x6 negatives not being flat in the holder. 6x4.5 negs in the same holder show this problem more dramatically.
So, I must have a go at glass carriers. Any recommendations? Can we get away with one piece of glass and a normal frame holder....etc.


Dave........

 

[keithwms]

Are you 'relaxing' the negatives before printing/scanning? I have the habit of cutting the negs and throwing them into a big book for a week before doing anything with them. Then they are super flat and print very well with a simple holder.

I figure that anything that prevents the use of glass is a good thing!

 

[fidget]

Hi Keith,
after developing them, I leave them for a few days in a book with weights on top to press them flat. When they come out they are flat across the width with a curve lengthways, in groups of 3 or 4. For the 6x4.5 I will try to find or make a carrier mask of the right size.

Dave...

 

[keithwms]

I see.

All I can say is that I have an ultra simple homemade holder that is nothing more than two pieces of metal contacting the film, and I have no flatness issues.

Dumb questions, don't mean to be insulting but: have you checked the parallelism of your enlarger e.g. with a grain focuser? Are you sure that the issue is with the neg holder?

 

[Toby]

I've never had any flatness issues with MF film. What I would say is you are adding four more surfaces to gather dust with newton glass holders.

 

[fidget]

Hi, thanks for the suggestions, all very welcome.
I think that the enlarger is set up all square, it is one with movements to do this so this is possible. I do use a grain enlarger but the problem with them is that it's not possible to view the edges or corners of the image. Also, if the enlarger were not parallel, I might not see an image fully sharp in the centre and going off sharp towards all sides. I thought that it was the camera lens, but I can see that the grain also goes mushy towards these areas, so some improvement may be possible on the enlarger.
The lens is not really a suspect, I have others to try though.
One quick way to check would be to check the grain sharpness across the projected image, any ideas on doing this? The normal focus scope will not work near the edges.

Dave...

 

[keithwms]

One very easy thing you could do is simply stop down your lens all the way and make a quick print, and make another quick print with it almost wide open, and compare. If the lens is very good and everything is aligned then there will be basically no difference except possibly some minor vignetting when you print a big enlargement with the lens wide open. But you can do this exercise at successfully larger enlargements, to work things out methodically. It is time well spent, in the long run.

To use a grain focuser for an alignment check I just open the lens up all the way, crank the enlarger all the way up to the top so that I have a large image, turn off the lights, and check all the sides. I also tried, using strips of paper or postcard paper, to make cropped images from the corners this way, to satisfy myself that everything was optimal. My enlarger was suprisingly misaligned. I suppose that there are also ruled/scribed glass plates that one could use to check alignment, instead of film. It would be nice to have a grid pattern. Say, you could probably print one on fairly thick plastic using an inkjet. I don't recall offhand where to get a glass one. Anyway you can simply use a grain focuser to check the corners, and that's all you need. The center should be fine if the edges are good. My initial problem was that two edges were basically fine but the other two were far off- a sure sign of tilt misalignment.

With a really crappy enlarging lens I suppose you could lose sharpness toward the edges but that would be a really crappy lens for you to be able to see it easily.


After my alignment check, I realized my next higher-order problem was minor variations in paper flatness, so then I started using printing frames, even with RC.

If at the end of the day it really is a film flatness issue then you may well need to invest in another holder, but I wouldn't use glass at all, that is such a headache.

 

[FrankS]

I don't have this problem and I use a 6x7 carrier (because it's the only MF neg carrier I have) to print 6x6 and 645 negs. I would question the quality of your enlarger lens or perhaps you are using this lens wide open without stopping down, which would increase DOF. I sometime tilt the print easel to alter the look of the final image and even then, with stopping down, there is no problem.

 

[fidget]

Thanks again, things to check.........
For MF I have a few lenses, Componon-S 80mm, Componon-S 100mm, Rodagon 80mm and even an old Minolta, a few to try. The normal lens is the first above, but i sometimes use the 100mm if the print is small, just to try it. I always arrange to use an aperture between 8 and 11, sometimes 5.6 for a big print.
The print which prompted me to post this thread was from a 6x4.5 which is of a landscape all at distance so no DOF issue. In portrait format, the neg was the end of a strip of 4, so sat at the side of my 6x6 neg holder. The soft side was the long side in contact with the frame. The side towards the middle of the holder was used to focus as this was actually near the centre of the 6x6 projection.
Just a thought! I could pick a neg which shows this effect (not at the end of a strip) and print a few times so that some prints have the side of the neg in the centre of the print and so on. I guess that this way I can at least eliminate the camera(s) from the "investigation".

Thanks, Dave...

 

[han1953]

There are three causes for negatives to buckle in the carrier:
1. the degree of moisture in the air of your DR is very much different from the place you keep your negatives. My solution: installing a moisture-absorber in the DR. This is not a great investment (about $10)
2. the negative carrier has no room for expansion. The all-metal carriers i use have a leeway of about 1/2 mm
3. the negatives get hot from the enlarger lamp. Just as with slides they tend to 'pop'.

 

[fidget]

Thanks for the ideas. I will follow up on these. I now have some 6x9 negs to try from my Moskva 5, these should be fun! My enlarger has only glass for this size.
Dave.....

 

[FrankS]

Thanks again, things to check.........
For MF I have a few lenses, Componon-S 80mm, Componon-S 100mm, Rodagon 80mm and even an old Minolta, a few to try. The normal lens is the first above, but i sometimes use the 100mm if the print is small, just to try it. I always arrange to use an aperture between 8 and 11, sometimes 5.6 for a big print.
The print which prompted me to post this thread was from a 6x4.5 which is of a landscape all at distance so no DOF issue. In portrait format, the neg was the end of a strip of 4, so sat at the side of my 6x6 neg holder. The soft side was the long side in contact with the frame. The side towards the middle of the holder was used to focus as this was actually near the centre of the 6x6 projection.
Just a thought! I could pick a neg which shows this effect (not at the end of a strip) and print a few times so that some prints have the side of the neg in the centre of the print and so on. I guess that this way I can at least eliminate the camera(s) from the "investigation".

Thanks, Dave...

Hi Dave,
Does this problem happen when you print a neg from the middle of a strip of negs? Do you see fuzziness all the way around the perimeter of the image or just one side. If it's jsut on one side, try reprinting with the neg strip inserted into the carrier in the other direction to see if the fuzziness follows the neg, or is related to the same side of the neg carrier. If the fuzziness follows the neg, the issue is in your camera.

 

[fidget]

Thanks Frank, Yes, I am quite keen to eliminate the camera(s). The bad neg was at the end of a strip, perhaps this had something to do with the soft edge. As you suggest, I print up from neg which shows this and then vary the position in the holder and print with very small aperture.

Dave..

 

[Finder]

Can you scan a print and show us the problem?

 

[fidget]

Hey, an opportunity to share an image!
I scanned part of the 9.5x12 problem print, shown in the first image.
The second and third images are crops of the centre of the print and the left hand side near the top, where it seems to be worst. This softness is really easy to see in the print and I would say that I should see it on the neg, but the neg looks fine.
The scan of the print looks a little more contrasty than the print.
The two crops are at the same resolution.

Dave..........

(A pic of La Catedral, the isolated rock to the right, well named I must say. On Tenerife)

 

[fidget]

Now that I have scanned it, it looks like the top is more affected.
This is the most pronounced effect i have seen to date. I suspect that some of my observations on other prints are related to the lens (on my Yashica Mat for example).
If a large part of "soft-towards-the-edges" seen on some of my prints is due to the neg popping or so, this could mean that my MF cams may be better than I thought, very exciting......