Enlarged negatives for cyanotypes.

[roy]

Thinking about the thread in another section about the RH Designs paper flasher, I was wondering if this could be used for film. I want to make some cyanotypes of white flowers where it is necessary to hold detail in petals etc., without over darkening the background. Bearing in mind the nature of the process, it will amount to putting a little more contrast in a selective part of the white area. If the negatives were being made by another means, it would amount to tweaking the curve but I am dealing with film here processed by conventional means ! Any recommendations ?

 

[davido]

hi roy
from my experience, creating detail in the hightlights with lith film is very difficult. It seems like it's a matter of finding the exact developing time/agitation amount so that the lith JUST reaches the right highlight density. lith film is really finicky and the highlights block up very quickly.
Ofcourse, if you're working with simply a high key image with no shadow detail then it will be much easier to obtain highlight detail.
With making the negative, flashing would, I believe, just effect the shadow detail, if anything. But if you are using an inter-possitive, flashing could work with that?
But that's just my experience. I have never tried flashing. Perhaps someone will have more promising information, which I would love to hear as well.
david

 

[davido]

I should also add that the contrast of the original image is also vital. I'm starting with B&W possitive transparencies ( ie. Scala) to omit the inter-possitive step. But, also, the B&W transparencies are already low contrast, so keeping detail in the hightlights or shadows (it seems you have to pick one or the other) is much easier when printing on to lith film. Otherwise, with a normal contrast original, one must use an extremily high dilution of developer with loooong developing times.
david

 

[roy]

hi roy
from my experience, creating detail in the hightlights with lith film is very difficult.

Thanks so far David. I have used Bergger BFPO 18 previously, which is an Ortho film.

 

[Loris Medici]

Hi Roy,

Which Cyanotype formula do you use? New Cyanotype is much much better in highlight tonality when compared to the classic formulation -> I strongly recommend that you switch to New Cyanotype if you value good tonality (especially in highlights). BTW, if you manage to expose / develop your negatives exactly matching the density range required by your printing process then you'll get all the detail you want in the highlights. Just determine your standart printing time and required DR using a 21 or 31 step tablet then make the necessary tests to determine the EI and development time to obtain the same DR with the negative / developer combination you opt to use. Phil Davis' "Beyond the Zone System" is a very good resource on this subject.

Hope this helps,
Loris.

 

[roy]

Loris, I shall be making an inter-positive and then contact printing that onto a negative so it is a matter of being able to retain and enhance the highlight detail during these processes. I wondered if flashing the film would help.

 

[nze]

As you use a 2 step method I will be far easier to keep the detail in the highlight without loosing detail in the black part.
You may do a small DR interpositive by exposing to have all the highlight detail and short developing to keep the detail in the black. so expose more and develop less. You should use film developer at this step such S23, rodinal etc... At the following step you will print to keep the detail in the low tone and expanse the contrast with the use of a high contrast developer such as D19 or any paper developer.

With the 2 step method you have more control of the result, adn in fact it fit any negative. The one step method is also possible with direct duplicating film but give less control to the DR

 

[roy]

Thanks Christian, certainly something to consider.