Durst 138 - negative inserts?

I have been unable to figure out how the negative holder in the Durst 138 works. The manual for the Durst 138s is not all that clear and my copy is actually quite fuzzy (literally - it is a low res pdf). Until only recently, I had no negative inserts to use with the holder, which has two glass inserts. I had to place the 5x7 negative on the glass and hope it remained straight when I closed the holder (it never did). Another local Photorio member (hexavalent) has a 138 and he brought over a box of parts for the negative holder but we still can't quite figure it out. For all of the formats smaller than 5x7, there is a pair of metal inserts which hold the negative. However, it looks like they must be used without the glass. In any case, I don't have a 5x7 insert for the holder.

If any of you 138 owners print 5x7 negs, I would love to hear from you.

The 138 series probably had the largest selection of neg carriers ever made for any enlarger, though the Durst 184 series was comparable in that respect. That's the problem. You need to post a picture of your parts or otherwise identify what you've specifically got. If you have a NEGA138 book-style holder with glass on each side, I recommend making your own downsized cutout masks using 10-mil opaque mylar and an X-Acto knife or razor blade. The overall dimension should cover the whole 5x7 glass area, but the central cutout be just barely bigger than your smaller negative. You can use these either between the glass just like your negative, or taped above the top glass.

Thanks for this, Drew. I have the NEGA138 holder as you describe, i.e., book-style with glass on either side. Hexavalent (my APUG darkroom colleague) has a box of inserts (two-piece, top and bottom) to hold the negative in place, for 35mm up to 4x5, and they all seem to fit just fine, but only if I remove the glass. If I understand you correctly, you are recommending that I NOT use the Durst inserts but cut my own from mylar. It seems crazy that Durst would go to all that trouble making inserts and not make one for 5x7, so I am still a little confused. I will get a photo of all the parts in question and I will post them sometime tomorrow.

I've got a bunch of those metal sizing frame too via horse trades - came with the horse, whether I wanted them or not. And I never do use them because I always want glass both sides. A lot of the flexibility of the Durst carrier system involved a puch system of their which is no longer available. There were also aftermarket suppliers of special carriers like Carlwen and Condit. But lots of commercial labs that used these enlargers were more into assembly-line production speed rather than optimum print quality, and therefore just didn't have the extra time to constantly re-clean carrier glass. No need to further complicate the discussion if your NEGA138 is in decent working order. I'll wait for your next post and then try to walk you through some simple inexpensive options.

I'd stick with the glass & make masks. The standard carrier (as opposed to the GRAHALON etc which Drew refers to) has pretty delicate spring tabs to hold the inserts which can break very easily. As for why no glassless holders for bigger than 4x5 - quite simply a question of keeping the negative flat under the heat of the bulb! More unsupported negative area, even on poly base, equals more chance of popping. The 138's a nice piece of kit & quite wonderfully compact for what it is. Kienzle in Germany can make custom inserts etc if needed.

What are you trying to accomplish? Print 5x7 without glass support? In that case I'd give up. If it is to print 5x7 on glass, you may have to fiddle with the negative after closing the glass if it shifts. All glass large-format carriers require that skill of the operator.

Durst made a Lapfe 5x7 insert for the Nega 138. I have one but have never used it because trying to print a 5x7 negative with out support as mentioned above is a waste of time. Using the glass inserts in the Nega 138 is the best way to print large negatives. I hold the negative secure by using a 3M post-it min tab on the edge of the negative and the glass which allows for the mask to be placed without everthing moving about. The post-it tab has low adhesion and is easily removed when done. I have found that anti-newton glass to be a must on the top level of the carrier. There is a Lapfe 5x7 on the big auction site if you want to look at one.
Gord

You could take an 8x10 sheet film and fully expose and develop it. Then cut out a hole to fit your 5x7 and trim the outside edges to fit the holder.

I scanned the instructions I have (and another version along with the service manual). You can see if those are clearer than yours. Page 9 shows the Nega 138, and 10 shows the LAPFE inserts which allow glassless use. I think Durst made 5x7 LAPFE mask, but I can't imagine wanting to use it because of negative sag. I sometimes use a tiny bit of drum scanner tape to keep the negative from moving.

I have been away from the computer for about a week, but here is where I am with this now.

I bought the insert that gordrob spotted on ebay (thanks, gord!). It should be here on Monday and I will see just how well it works. I don't have to worry about negative pop from heat because I am using an LED bulb. So, if the negative doesn't sag at all in the LAPFE insert, that might be the solution for me. Some of you seem to think that glass is the way to go but isn't it just an extra four surfaces to clean? Nonetheless, I might try Drew's suggestion and cut an insert out of mylar for use with the glass, just to see if it makes any difference.

In any case, I will be doing some testing with all of this sometime next week and I post with the results.

Larry, those manuals are much clearer than the ones I have. Thanks a lot.

An old thread, showing my modified Nega MC to take the Lapfe inserts

Doc W said:

which has two glass inserts

Click to expand...

There are two kinds of glasses, regular flat glass and Anti Newton Ring




Let me add some things...

When you insert the Nega 138 carrier at around of half of the insertion you will notice a hard point, the carrier is half inserted and those crosshairs that are in the frame will be projected on the middle of the easel, offering a great oportunity to nail focus with convenience and precision, then you complete the Nega 138 insertion.

Those crosshairs are in an slide that can be adjusted higher or lower to match the film plane, you have to calibrate that by using a negative with sharp edges and checkn .

You may have one ANR glass and one regular glass, the ANR glass edged (slightly frosted) surface should be in contact with the emulsion side of the film, for the case you reverse the image.

If you have two regular glasses (no ANR) probably usually you won't see newton rings anyway because the the glasses are very flat and pressure will not allow much the film-glass clearances that provocate the rings, but some films may benefit from having an ANR glass.

If the ANR in the bottom side it won't degradate image, I tested it and personally I found no practical damage, absolutely.

IMO glass carriers are the perfection, but you should control dust specially with them. If you don't have it, just get a cheap HEPA air purifier, personally I use a Honeywell HAP 16000, I use a programmer



to start the purifier 10min several times per day to keep the room clean, and of course I start it for anything from drying film to scanning, or operating the 138.

Let me also recommend a lubricant for all the 138 mechanics, I move mine with a single finger, impressive: