'Ordinary' film

I am wanting to make a neg with 'ordinary' film and therefore need to convert from pan sensitivity. Although I suspect it may not be possible to make a true reproduction would it be a simple matter of using a blue filter? If that is the case is there any particular type or colour of blue filter or are all 'blues' the same? Would the Cokin type be suitable and what density? Density may only have effect on exposure time - but I don't know.
Any suggestions?

Panchromatic films are plain ordinary every day films, I guess you mean Orthochromatic

Why not just use Ilford Ortho Plus although it's not available in mimiature sizes.

Ian

Thanks for the reply.
The thing is I want to try to replicate the very early photographs which were photographed with film only sensitive to blue light. In the early days, once ortho had been invented, this film was referred to as 'ordinary' film. Hence my interest in wanting to revert to blue only sensitivity.
Size-wise I use 5x4 and 5x7.

hi colin

would paper negatives work for you ?
they are orthochromatic, and slow and like olde filme .. sort of.
since you are shooting large format its easy ... ( and maybe already in your darkroom ).

you could also coat your own ( i like doing that these days ) with liquid emulsion
and regular paper, or glass. the only thing about the glass is you need plate holders
and it takes practice coating it ... paper is a piece of cake ...

good luck !
john

Paper negative on graded paper maybe? I've recently shot a few paper negs but on MG which is sensitive to green and blue.

To me in this context ordinary film would mean unsensitized film, thus blue-only sensitive.
To achieve that a blue color-seperation filter would be best.

As you are busy with large format a X-ray film of the unsensitized kind could be an alternative if at hand.

Blue filters are not that common, however 80A was very common. You don't have one of those laying around?

Paper negs?? Good call, trouble is I don't have a darkroom. I have given thought to paper negs before, simply to try them, but got no further. No darkroom?so what do I do? - Salt prints, I can get away with a large Harrison tent thing for loading and then dev in a Paterson 10x8 colour processor and subdued light for coating. Although I'd really like to give paper negs a try, I might get as far as getting a negative but printing would be the next problem. I don't know how they would work for salt prints and only UV light.
So, as much as I definitely like salt prints, they are really the only printing I do (other than those other unmentioned type). So I'm back to the blue filter situation.

hi again colin

bummer, no darkroom ..
can you get a safelight red-bulb, and replace a room light with it ?
i do that on occasion, it works OK ...
...once you have the image you could get a hot plate and paper towel, cloth (to protect the paper)
and some bees wax or parafin and translucentize your negative.

the original salt prints were done on paper negatives, people have been waxing paper
negatives since around the same time ...
it might be something to think about if the blue filter doesn't work

if you coat your own with liquid emulsion it is pretty slow ..
i use butcher paper for my paper negatives, it is plentiful and CHEAP ( and THIN ) ...
can't say how archival it is though ...

good luck !
john

I do a fair amount of optics system design at work for medical devices so forgive me for the more complicated answer than any sane (non-geek) person would actually want

Well, a blue filter would get you part way there. For a given process, there is a graph that describes the sensitivity as a function of wavelength. Here is an example provided by Joe Smigel for wet plate with different proportions of iodide vs bromide salts. Now, compare that to a 80A Hoya filter. As you can see, the spectral transmission graph of an 80A blue filter shows a peak transmission around 440 nm and still lets some red light through all the way into the far red while an iodide emulsion has a peak out to 420 and completely insensivity at 440 and beyone. What does all this mean? It means that a blue camera filter will only get you part way there, but it may be far enough for the look you want. To really mimic the spectral characteristics you'd need a bandpass filter like those at Edmund optics.....the off the shelf filters tend to be small and very pricey.

End of long, geeky explanation...

Don't forget that with your examples the opacity of the filter (though limited) and the high in-sensitivity of the emulsion add up.

(maybe weird wording; but I guess very understandable for a geek...)



By the way, you refered to colour conversion filters. Colour separation filters are much steeper.

I'd suggest using ortho sheet film, which should be easily available by order if it isn't in stock, as that is still made by Ilford, Agfa (branded Maco or Rollei) and Foma (probably, depends on the importer).

Loading and development could be done as you are working now, using the changing tent and the Paterson processor. Last time I was in the UK was a few months ago, but I recall it getting dark every evening - this will be a great help in blocking light from some small room or other, if you wish to set up a temporary darkroom. There is no need for running water or a drain in a darkroom as these can be in an adjacent, normally lit, room without much trouble (I have produced up to 16x20" prints in my darkroom with this arrangement).

Another alternative would be to use a paper negative, choosing a fixed-grade paper which is pretty much orthochromatic. Pre-flashing can assist you in contrast control if necessary. You might also look at the direct-positive paper from Ilford. The paper negs could be developed in your Paterson processor after minimal experimentation, if you have no alternative.

Final prints could be by contact-printing frame which you are probably already using for your salt-prints. Slow speed contact-paper is still available from (for example) Foma, so you could use the temporary darkroom idea and expose on to this material, or even ordinary paper, using a lightbulb as a light source.

It sounds an interesting and fun project. Good luck

AgX said:

Don't forget that with your examples the opacity of the filter (though limited) and the high in-sensitivity of the emulsion add up.

(maybe weird wording; but I guess very understandable for a geek...)



By the way, you refered to colour conversion filters. Colour separation filters are much steeper.

Click to expand...

Fair enough. I'm not familiar with color separation filters, but it makes sense that they would be steeper given their function. I just used an 80A as an example since it is generally available in a variety of sizes.

I just looked at the Ilford site and the response dies around 570nm for Ortho and 650 for Delta 100. I think the folks who are saying to try Ortho Plus are on the right track if the OP can use 4x5. That combined with a blue filter (separation if you can find it, 80A otherwise) might be the best in the end.

You could use a number 47 or 47B Wratten filter. Both transmit blue light, cutting off everything above 500nm, the 47B is sharper at 500. Both will simulate the original blue only film look with panchromatic films that you desire. B&H carries both filters in various sizes.

I got this information from the old "Transmission of Wratten Filters" book.

A book anyone interested in these matters should have at hand. Actually it doesn't matter what edition.

I found it online, and printed out the pages that have the info I need for my work as a reminder for filter factors and exposures. Another handy one is Kodak's Reference Handbook. I found the 1 from 1946, it includes images showing the range of several filters. I found both in a photography forum, unfortunately, I can't remember which one.

By using the first one, I can use it to calculate out proper exposure with my filters. As you said, no one using filters should be without one! (At least, when starting out, like me!)

Mark Fisher said:

It means that a blue camera filter will only get you part way there, but it may be far enough for the look you want. To really mimic the spectral characteristics you'd need a bandpass filter like those at Edmund optics.....the off the shelf filters tend to be small and very pricey.

Click to expand...

A blue dichroic has a pretty sharp cutoff around 470nm. For something a little shorter, perhap the Hoya B370 would be better - The dichroic filters would be around £18 for a 25mm Ø unmounted, a B370, expect to pay upwards of £35 for a one off.

I've used UQG in the past, and they can cut custom sizes out of a range of specialist glass, but expect to pay accordingly.

I just looked in Ansel Adams' The Negative and several other websites, and found that the spectral response of blue only film matches almost perfectly to the 47B filter. The film died out at 500nm, which is where the 47B cuts all light. The response of the filter suggests that at 430nm a 1 stop adjustment in exposure is required, getting higher as the color shift away from its "center," allowing only 0.17% of light at 500nm. The 47 is sharper cutting at the 340-430nm end, but higher over the rest of the blue end.

I hope this will help. B and H has the filters reasonably priced, and I'm sure you can find it elsewhere cheaper!

What a great and varied response, thanks to everyone with their input and suggestions. APUG rules.

AgX said:

To me in this context ordinary film would mean unsensitized film, thus blue-only sensitive.
To achieve that a blue color-seperation filter would be best.

As you are busy with large format a X-ray film of the unsensitized kind could be an alternative if at hand.

Click to expand...

If the film is unsensitized it will not record light at all.

Yes, my wording was nonchalant: Of course I meant film with an emulsion not spectrallly sensitized

It will record in the blue and a bit in the UV (hampered by the gelatin) region due to the inherit sensitivity of the AgX.
This sensitivity is enhanced by adding so called chemical and spectral sensitizers.

Damn.......this is getting me interested in trying a 47B or the B370. Great stuff. I had no idea this stuff was available in anything else than the silly expensive lab quality filters.

Ansel Adams recommended the 47B, and after looking at the manual on filters, I can see why. Unfortunately, I don't know the B370, and it doesn't seem to be in the manuals I have.

If you go through B&H, I know they have them available, and Amazon has several from Tiffen listed in different sizes, in prices ranging from about $20-$100. In fact, I may have to get 1 for me as well, for when I'm shooting in the shade without sky in the scene!