some interesting filmstocks

[Fandyus]

So today I've been browsing FotoŠkoda, a local camera gear seller, they also sell films. I ran into this weird french enterprise which claims to be "world's smallest film company".

They make several interesting filmstocks.

https://filmwashi.com/datasheet/Z_en.pdf

Washi Z 400, which is sensitive up to 750nm and has the iso of 400.

https://filmwashi.com/datasheet/S_en.pdf

Washi S 50 which has extremely high contrast, sensitive up to 620nm, ISO of 50, they claim that this one is used to capture sound, you read that right, sound. I have no idea how that works.

 

And the one that intrigues me the most.

 

https://filmwashi.com/datasheet/F100_en.pdf

Washi F 100 which is only sensitive up to 575nm and is an xray film. I wonder if it would be a good idea to use this one for UV photos. I would like to try to do that. Best thing about this one is that it's just not sensitive to infrared so I could do some wacky things with it without fearing leakage. Maybe something like taking several hour long UV exposures at night to see what comes out. I have several other B&W filmstocks in my fridge but I'm not sure how good those would be. I have some ADOX CMS II PRO which is out due to it's high contrast, which would make it impossible to nail exposures, I also have some Ilford PAN 400.

Alternatively I have been considering getting a roll of Fomapan 400 or Ilford HP5+. I picked HP5+ for it's insanely low contrast and under/overexposure tolerance and Fomapan because it's very cheap here. The Fomapan however is quite panchromatic so I might have to start blocking IR which would make the whole thing less effective and would defeat the purpose of using film imho.

[dabateman]

Fuji instax film is surprisingly sensitive to UVC.  I just needed 15 minute exposure time with a 15W Mercury bulb.

Its more sensitive to UVA, only 2 seconds. 

 

This Diana square instax film camera with the premium 75mm glass lens is sensitive from 350nm up.

https://shop.lomography.com/en/cameras/diana-instant-square/diana-instant-square-camera

 

The stock plastic lens is only good down to about 385nm, maybe 380nm best. I have them as well as the NONS camera,  that takes mini instax film and any lens. 

 

This is where I posted my Nons tests: 

https://www.ultravioletphotography.com/content/index.php?/topic/4306-nons-camera-with-fuji-instax-mini-film-tries-uv/&do=findComment&comment=41886

 

[Fandyus]

I'm familiar with this post of yours, it's not what I intend to be doing.

What I want to do is UVA photography, I would perhaps like to exploit the fact that film comes in relatively fast speeds and should theoretically be way more sensitive to UV than digital sensors with a Bayer array. Plus films the likes of HP5+ might make it feasible to do landscape photography in UV without blowing out the sky or having no information in the shadows.

[OlDoinyo]

Either of the second two emulsions would probably be fine for UVA with a simple Wood's-glass filter; in terms of sensitivity I doubt it will make much difference which you use (unless there is something about them I do not know.) The high-contrast film may require a special developer if you want continuous-tone results (such as Technidol.) The extended red emulsion would require an IR-blocking filter for UV work. 

 

You will find that there is much less difference in sensitivity between fast and slow films in UV compared to their visible-light ratings. Example: an ISO 3200 film is normally 5 stops faster than an ISO 100 film, but in UVA the difference will be more like 1.5-2 stops. You can, however, still push film for additional speed. I have achieved daylight equivalent sensitivities of ISO 50-100 with Ilford Delta 3200 film, which is a lot faster than many digital sensors. However, if you take a late-model digital camera (which I do not have) and crank the sensor gain to 204800 or beyond, you may achieve sensitivities beyond what film can obtain (at least above 330 nm.) I don't know, personally.

[dabateman]

From the films I have tried in UVA with a Baader venus u filter,  the film and digital camera sensor were about equal in UVA response. 

Film is much better in UVB and maybe even UVC.

But for just 350nm and up, I would stick with digital.  Even a Sigma Foveon camera, monochrome only is better than film in just UVA. The Foveon sensor isn't sensitive at all to UVB. So in the long run a SDQ or SD14 with removable dust (uv blocking filter)  might be better than film.

[OlDoinyo]

I used to own an SD14 and did a bit of UV with it. I got some usable results, but it was definitely not faster than film (nor even as fast as my converted A900.) I do admit that the removable hot mirror was handy.

[Fandyus]

15 hours ago, dabateman said:

From the films I have tried in UVA with a Baader venus u filter,  the film and digital camera sensor were about equal in UVA response. 

Film is much better in UVB and maybe even UVC.

But for just 350nm and up, I would stick with digital.  Even a Sigma Foveon camera, monochrome only is better than film in just UVA. The Foveon sensor isn't sensitive at all to UVB. So in the long run a SDQ or SD14 with removable dust (uv blocking filter)  might be better than film.

I guess that works for you. I have an EOS 1100D with miniscule dynamic range and terrible noise performance. And I just like film anyhow. That's why I want to try this.

On 11/14/2021 at 6:02 AM, OlDoinyo said:

Either of the second two emulsions would probably be fine for UVA with a simple Wood's-glass filter; in terms of sensitivity I doubt it will make much difference which you use (unless there is something about them I do not know.) The high-contrast film may require a special developer if you want continuous-tone results (such as Technidol.) The extended red emulsion would require an IR-blocking filter for UV work. 

 

You will find that there is much less difference in sensitivity between fast and slow films in UV compared to their visible-light ratings. Example: an ISO 3200 film is normally 5 stops faster than an ISO 100 film, but in UVA the difference will be more like 1.5-2 stops. You can, however, still push film for additional speed. I have achieved daylight equivalent sensitivities of ISO 50-100 with Ilford Delta 3200 film, which is a lot faster than many digital sensors. However, if you take a late-model digital camera (which I do not have) and crank the sensor gain to 204800 or beyond, you may achieve sensitivities beyond what film can obtain (at least above 330 nm.) I don't know, personally.

Thanks a lot for the info! Is there any particular filmstock you'd recommend?

[OlDoinyo]

Most B&W film will work; I use Delta 3200 primarily to squeeze the most speed out that I can. It is possible that Tmax3200 would work almost as well, although I have not tried. I have used Tmax 100 and Tmax 400 for slower-speed work, as they have fine grain and good tonality. I used to use Shanghai GP3 for medium-format work, although there were quality-control issues with that; but it was very cheap. There are a lot of films out there I have never used and about which I know nothing. B&W film enthusiasts often have their favorite emulsions and developing recipes; you can find a lot of discussion of these topics on websites such as Photrio, Pentaxforums, or the photography subs on Reddit. It all comes down to what grain/tonality properties you prefer; I don't think you will find much difference in UV sensitivity between equivalent products from one maker vs. another. Most of the film sensitization technology was concentrated on boosting and tweaking visible response. Any effect on UV sensitivity was incidental. And any film whose response cuts off at 690 nm or less will not need an IR-cut filter for UV work.

[OlDoinyo]

My theory about the sound recording: many motion picture prints had the soundtrack recorded in the margin by an optical scheme. A light next to the film was modulated according to sound wave amplitude and was shone through a radially-graded ND filter onto a high-contrast emulsion. The result was a stripe that varied in width according to amplitude recorded. Playback was achieved by shining a steady light through the traveling film onto a photosensor and amplifying the resulting signal. The scheme had fairly low fidelity but was cheaper to implement than magnetic tape and less prone to accidental erasure. Perhaps the second emulsion described had something to do with this process.

[Fandyus]

On 11/15/2021 at 3:53 PM, OlDoinyo said:

Most B&W film will work; I use Delta 3200 primarily to squeeze the most speed out that I can. It is possible that Tmax3200 would work almost as well, although I have not tried. I have used Tmax 100 and Tmax 400 for slower-speed work, as they have fine grain and good tonality. I used to use Shanghai GP3 for medium-format work, although there were quality-control issues with that; but it was very cheap. There are a lot of films out there I have never used and about which I know nothing. B&W film enthusiasts often have their favorite emulsions and developing recipes; you can find a lot of discussion of these topics on websites such as Photrio, Pentaxforums, or the photography subs on Reddit. It all comes down to what grain/tonality properties you prefer; I don't think you will find much difference in UV sensitivity between equivalent products from one maker vs. another. Most of the film sensitization technology was concentrated on boosting and tweaking visible response. Any effect on UV sensitivity was incidental. And any film whose response cuts off at 690 nm or less will not need an IR-cut filter for UV work.

I was thinking I could maybe even eventually stand develop the film at home, wljld give best results with UV anyhow. I'd probably either use Fomapan or HP5+.

Thanks for all the info!