Enlarging bw C41

Boris Mirkov · Feb 18, 2019

I have tried to enlarge Kodak BNW 400CN in 35mm with black and white chemistry and the paper is completely unresponsive, literally nothing comes out. Is there any way to do it in bw chemistry and papers or is it doomed for colour enlarging?

MattKing · Feb 18, 2019

It should work fine, withlonger exposure times and just a bit of a contrast challenge.
What light source is on your enlarger? If it is a cyan source, the mask might be creating more problems than for most.

Rudeofus · Feb 18, 2019

AFAIK Kodak's BW400CN is intended for RA-4 enlargement, and it has an orange mask like color film. It should also be lower in contrast than typical B&W negatives. It should be possible to get B&W prints from this film, but you have to either deal with very low contrast, or print at gradation 5 and still get low to moderate contrast.

bvy · Feb 18, 2019

XP2 prints beautifully on black and white paper...

Boris Mirkov · Feb 18, 2019

So the times must be much longer than I anticipated, will try tomorrow with longer (much longer) exposures. I did colour enlargements on bw paper, it did take more time and did produce lower contrast so I am a bit confused as to why my papers got out white. I will report on the progress

Rudeofus · Feb 18, 2019

One shall not underestimate the density of this orange mask. If you look at the data sheet here, blue layer starts at density 1.0, green layer starts at density 0.7 - 0.8. This means you need 5-10 times the exposure that you would need with regular B&W film.

pentaxuser · Feb 18, 2019

bvy said:
XP2 prints beautifully on black and white paper...

bvy, so with XP2 Plus do you need 5-10 times the exposure of B&W film and if not what is the multiplication factor 1.5, 2 etc

Rudeofus, would the densities of the 3 colour layers not also apply to XP2Plus to the same extent and is the orange mask with Kodak BW400CN much denser than the mask of XP2Plus

Thanks both

pentaxuser

MattKing · Feb 18, 2019

There is no orange mask on XP2. It works better with black and white paper, but is much more difficult to print on (minilab normal) colour paper. The masked Kodak 400CN film gave better results in a minilab environment.
Different horses, for different courses.

bvy · Feb 18, 2019

pentaxuser said:
bvy, so with XP2 Plus do you need 5-10 times the exposure of B&W film and if not what is the multiplication factor 1.5, 2 etc

It does require more exposure but nothing like five to ten times. Looking at my notes, it's more like 1.5 times. That's a rough estimate though.

pentaxuser · Feb 18, 2019

Thanks bvy and Matt. For all others as well as bvy and Matt with information: So there is an orange mask with Kodak that is absent with Ilford XP2Plus and that presumably accounts for some of the extra exposure required. What of Rudeofus' colour layers info? Are they present or absent in XP2 Plus

Presumably the same colour layers in Kodak BW400CN and orange mask are also present in C41 colour negs? If so I have printed some of those negs on B&W paper and while it was some time ago I feel sure that if those colour negs had required 5-10 times the exposure I'd have remembered that. All I can say is that when I printed I think I'd have remembered if the colour neg had required a longer exposure to the extent of 5-10 times.

So is there something that distinguishes Kodak BW400CN exposure from colour neg exposure on B&W paper?

pentaxuser

Rudeofus · Feb 19, 2019

pentaxuser said:
So is there something that distinguishes Kodak BW400CN exposure from colour neg exposure on B&W paper?

The biggest difference will be red areas in your subject matter. With BW400CN this will be rendered orange+gray against orange, so after filter correction it will print alright. With color negative film this will print as cyan+orange against orange, and will leave no image on your B&W paper.

pentaxuser · Feb 19, 2019

Thanks Rudeofus. So is there a difference between the effect of the colour layers in BW400CN and XP2Plus that accounts for say 3.5 to 8.5 times the exposure required for BW400CN and what bvy has given as the extra exposure for XP2Plus which is 1.5 I quote these figures because bvy mentioned 1.5 times exposure for XP2Plus and you mentions 5-10 times. My reading of your post suggests to me that in terms of extra exposure it may be all down to the orange mask? Is this a correct interpretation?

In your post 11 it sounds as if a red area on BW400CN will leave no image on B&W paper. Does this mean that a red car appears as as simply a white outline of the car's shape on B&W paper or a solid black image? Either way it sounds as if the OP is doomed to failure in terms of capturing any red object on his BW400CN frame on B&W paper?

Thanks

pentaxuser

Rudeofus · Feb 19, 2019

pentaxuser said:
Thanks Rudeofus. So is there a difference between the effect of the colour layers in BW400CN and XP2Plus that accounts for say 3.5 to 8.5 times the exposure required for BW400CN and what bvy has given as the extra exposure for XP2Plus which is 1.5 I quote these figures because bvy mentioned 1.5 times exposure for XP2Plus and you mentions 5-10 times. My reading of your post suggests to me that in terms of extra exposure it may be all down to the orange mask? Is this a correct interpretation?

XP2 developed in C-41 chems should look like normal B&W negative film. If this film has some slightly higher b+f, then it will need the extra exposure described by bvy. BW400CN, on the other side, has this orange mask, which appears like a deep orange filter slapped on top of regular B&W film. This deep orange filter gives you a lot of extra density for green and blue light, so your enlargements will need a lot more extra exposure than what you would need with XP2 or regular B&W film.

pentaxuser said:
In your post 11 it sounds as if a red area on BW400CN will leave no image on B&W paper. Does this mean that a red car appears as as simply a white outline of the car's shape on B&W paper or a solid black image? Either way it sounds as if the OP is doomed to failure in terms of capturing any red object on his BW400CN frame on B&W paper?

That red car will look black. Whatever red light it emits, will expose mostly the cyan layer of color negative film. This cyan layer (you can call it minus red layer if you want) only affects red light component from enlarger lamp and will leave no trace on your B&W paper.

This, of course, does not apply to BW400CN film, since this film registers all visible light as gray. The "red car" ---> BW400CN ---> B&W paper route will give you a normal looking B&W image, assuming you get the orange mask and the low contrast under control. The "red car" ---> color negative film ---> B&W paper route will give you pics which resemble the ancient "orthochromatic" look.

pentaxuser · Feb 19, 2019

Thanks rudeofus, so in summary the real difference between prints on B&W paper from a Kodak BW400CN film and an Ilford XP2Plus film is simply the exposure time due to the orange mask?

We await the results of Boris' fresh attempts now he knows the facts and is increasing his exposure times considerably. He does not say what his original exposure times were that unfortunately did not even give a hint of a print. What sounds worrying and may indicate some other issue is that he was aware of the need to expose longer from his B&W prints from colour negs so I infer he has already extended his exposure time when attempting B&W prints from the BW400CN and yet not even a glimmer of an image

pentaxuser

Enlarging bw C41

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