Newton rings

[Jepperxx]

Hi there. I use an durst m605 colorhead and a durst m805 colorhead and ive been using a durst glass upwards and a mask downwards . For the most i can avoid newton rings but lately i have had them to often. Why is this? I thought the glas which is a original glass for the neg carrier ( i have several of them) was an antinewton glass but obviously not.is there anything i can do to avoid hem with this glas or should i buy new glass?

 

[Hilo]

Just making sure:

the negative must be with the glossy side facing up and the AN treated side of the glass facing down touching the glossy side of the negative

 

[Jepperxx]

Thanks hilo. I never thougt much about this as i allway assumed hat it can only turn one way in the negative carrier to prevet mirrored image and the glas can only sit one way in the negative carrier ?? Is this wrong assumed?

 

[Jepperxx]

…but now that i come to think about it i must tjek out this right now

 

[Jepperxx]

Hmmm. Hilo …Can you tell me which side is the glossy side on a colornegative… ?

 

[Jepperxx]

…i cant see any difference ..they are both equal glossy..also IF the glass in my carrier is a AN it can only sit one way with those cut edges so that part is , i assume, ok.

 

[AgX]

Maybe the surface treated side of the glass got fatty.

 

[Hilo]

I do b/w only and with film one side is clearly glossy. I have no experience with color film. But the correct position in the negative carrier is (from when you look at the image as you took it) just turned 180 degrees with the same side upwards. From your description I take you do it correctly. But I am confused by your words: "ive been using a Durst glass upwards and a mask downwards". Does this mean no glass is pressing on the negative from above?

So if one has a negative carrier with two glasses, it is only the top glass of the neg carrier that is AN treated and compared to the bottom glass it is slightly less clear. If they're the same you have 2 normal glasses in your carrier. This happens.

I think we need someone here with color negatives experience. Because if it is true that both sides of the film are glossy, then I assume your bottom glass touching the film from below can also cause newton rings . . .

 

[Jepperxx]

Ok hilo. I have several of durst glasses so i will look at every one . What i mean is that i use glass upwards to protect negative from heat and downwards just a mask. What i think after reading your last post here is.,1. i think that the nagative touches the glas ( maybe)
2.: maybe its a just plane glass ..maybe i have mixed them around by time because i didnt know there could be a diffrence in the upper and lower glass ( if one uses this setup) .

 

[Jepperxx]

… and maybe my negatives isent flat enough …maybe i should give them more time flattening under my big heavy books

 

[ic-racer]

Durst AN glass is not totally clear or shiny. You should be able to tell by looking.
In your setup, with glass on top and a mask below, the negative will be positioned with the base side upward. You will know it is correct if it projects correctly right-to-left.

 

[Jepperxx]

Well.. ive looked at the same 7 glasses and there is no difference i surface ..all clear at each side. Then i took a gebe 6x6 diaframe with AN glas apart to compare and here i can see that the glass is not clear.. i guess this is how its suposed to be

 

[Jepperxx]

Thanks ic. I guees i havent been so lucky that i got a AN glass with those 3 color enlargers i have bought over the passed two years. And all along i thought it was. So ive been kind of lucky avoiding Newton rings on the 10 50x50 prints i have framed on my walls…well they are mostly night shots and a couple of daylight shots without rings. They show up from time to time and then i of course trow them out.

 

[Jepperxx]

Hahaha.. i looked again among the 7 glasses holding them up in the light and i found one! yes its very obvious. This has been lying in the drawer in two years. Thank you guys for your great inputs!

 

[Hilo]

That's so nice, bravo! If you plan to keep this enlarger you should consider finding some more AN glasses for it. When we have time, this is not difficult. You may know you can search in Ebay and then "save this search". Then you get an email when the item you want is listed . . .

 

[Jepperxx]

Hi hilo. Yes id like some more AN glass. Ill search ebay or others .. i found some in fotoimpex berlin also

 

[DREW WILEY]

Hold the glass toward a lightbulb. The plain side will sharply reflect the light source; but the reflection on the anti-Newton side will look slightly diffused or blurred. If not, then you don't have AntiNewton glass at all. And ideally, you need to sandwich the film with glass on both sides, or it won't be held flat, and that fact might defeat the whole purpose for using AN glass to begin with - the contact across the whole film surface needs to remain truly and consistently flat. I personally use AN glass both above and below the negative. The film should be TIGHTLY sandwiched between these. I've posted on the details many times before.

As far as the film itself goes, the emulsion side, which should face downwards in the carrier, is less shiny that the base side.

 

[Steve Goldstein]

<snip>

As far as the film itself goes, the emulsion side, which should face downwards in the carrier, is less shiny that the base side.

I found it difficult to distinguish the base and emulsion sides of TMX in 120 (the only version of TMX with which I have experience) when I was printing a negative for someone else because the emulsion side was surprisingly shiny. The frame numbers and other edge markings saved the day.

 

[AgX]

Hold the glass toward a lightbulb. The plain side will sharply reflect the light source; but the reflection on the anti-Newton side will look slightly diffused or blurred. If not, then you don't have AntiNewton glass at all. And ideally, you need to sandwich the film with glass on both sides, or it won't be held flat, and that fact might defeat the whole purpose for using AN glass to begin with - the contact across the whole film surface needs to remain truly and consistently flat. I personally use AN glass both above and below the negative. The film should be TIGHTLY sandwiched between these. I've posted on the details many times before.

As far as the film itself goes, the emulsion side, which should face downwards in the carrier, is less shiny that the base side.

Well, typically the AN-surface in such case is pressed againt the glossy side, the side being the typical cause for Newton-rings. The plain glass surface then is pressed against the emulsion side, the side being the lesser cause for Newton-rings.
But it much depends on the very film and its surface design.

 

[ic-racer]

Thanks ic. I guees i havent been so lucky that i got a AN glass with those 3 color enlargers i have bought over the passed two years. And all along i thought it was. So ive been kind of lucky avoiding Newton rings on the 10 50x50 prints i have framed on my walls…well they are mostly night shots and a couple of daylight shots without rings. They show up from time to time and then i of course trow them out.

I actually thought the same. That is my first Durst 10x10 glass carrier I thought was AN glass... until I got a second one and realized the first one was plain glass on both sides. I never got any rings, however, with the plain glass carrier. But I think that is because the Ilford Hp5 8x10 film does not form Newton rings easily.

 

[DREW WILEY]

Some of the older black and white sheet films had a fair amount of retouching tooth to them. That certainly helped. Now many are fairly slick and make it more difficult to control rings. There were once a number of types of AntiNewton glass, with Durst having one of the best. The sources today are more limited, but relatively good. My most recent batch came from ScanTech in the Los Angeles area. How bad an issue rings are depends on the climate, with drier climates having less of an issue, and damper ones being more of a challenge. I personally live in a foggy coastal climate where rings are a constant problem. Anti-Newton glass is essential on both sides here.

Recent Kodak color sheet films like Portra and Ektar have a bit of surface texture which allegedly improves scanning; but it also reduces rings a little too, but not enough to forego actual AN carrier glass. Thin 120 film presents the biggest challenge.

In the past, Anti-Newton aerosol sprays were available, which if properly used, mitigated the film slickness problem. But these are no longer available, apparently due to now-banned nasty components. I always used t\hem under the fume hood anyway.

 

[Patrick Robert James]

I use anti newton glass on top and regular glass underneath on my Saunders 4x5. On my Focomat's custom carrier, the glass underneath is coated which is nice. I've only ever had newton rings from the emulsion side once that I can recall, and that was with Acros on the Saunders regular glass. It can be mitigated with corn starch though. Just a poof of corn starch in the air and wave the neg through it. Solves the problem.

 

[DREW WILEY]

Finely sifted corn starch was once termed "offset powder" in the printing industry, although certain other products might have been too. Starch can hypothetically work, but is just about the last thing I'd want to get inside an enlarger creating dust and attracting booklice. And it doesn't work well except at modest enlargement. The official spray worked better due to a thin lacquer-like binder material, but also contained the same nasty solvents as butyl acetate print lacquer. In either case, the idea was to work beneath gentle fume hood ventilation, spray or squeeze-bottle a little cloud-like puff into the air, and before it dissipates, swish your negative through it.

Acros is especially a pain in the butt due to emulsion slickness, even in large format. But it's also a wonderful film. My 8x10 cold light enlarger had specially optically coated Zeiss glass in the carrier, and most of the time it worked, but not for Acros, so I later put true AN glass in there just like all my other enlargers. But even in that case, I have be careful on cold winter days when condensation is a potential problem. I pull the carrier out along with the glass, and turn on the passive electric heat several hours in advance of the work session. I'd rather do that than have the excessively low humidity of forced air gas heat.