Discussion of Collodion Emulation

[photoni]

Just did a quick experiment in the garden. Three filter setups, i) Schott S8612 1.5mm with Baader UV/IR cut (similar to internal filtration on normal unmodified camera), ii) Schott S8612 1.5mm plus BG25 3mm, iii) Schott S8612 1.5mm plus 1.5mm ZWB3.

 

Photos taken on a multispectrally modified Canon EOS 5DSR, with a 40mm f.28 pancake lens. Settings f8, and ISO800 for all. Images saved as JPEG in camera, and then desaturated and auto contrasted in Photoshop before shrinking for sharing.

 

1. 'Visible' light, S8612 (1.5mm) plus Baader UV/IR filter

 

2. BG25 (3mm) plus S8612 (1.5mm)

 

3. ZWB3 (1.5mm) plus S8612 (1.5mm)

 

The BG25 does look different to the 'visible' one, with softer shadows and a lightening of the sky. The magnolia buds in the tree on the left also look darker. There is a bit of a difference between the BG25 and ZWB3 one, but more subtle. I do admit it was a quick and dirty experiment though, so take from it what you will.

 

JMC Thanks, the photos with the collodion outside can be recognized because the sky is very clear,/white, the clouds are not seen, then scene are very contrasted.

The peculiarity is above all in the portraits where it highlights the freckles, the spots, the wrinkles ... it ages a lot :)

I did some tests with the few filters I have, as a "signal" I used some flowers to understand if the Sony A7 full spectrum that I received a few days ago works

it seems that with BG25 the normal Nikon Z5 Z7 D810 go better :-(((

[dabateman]

Wow that z7 with bg25 looks great.

 

[photoni]

How about this: Sensor + BG3 (1.5 mm) + S8612 (2 mm), black curce, normalized. But the sensor curve looks odd, let me check... Yes, sorry, I added an extra zero in a few places, fixed. This is as before, but the correct version: Still not bad.

 

Stefano ... I just gotta get the chemists right, gotta find the hydrometer, the ph meter ... I'm messy

[OlDoinyo]

Somewhere I seem to recall a conversation with someone about using an IR-blocker stacked with MidOpt's 510SP filter to emulate the response of wet-plate emulsions. Is that easier or more difficult than what is being discussed here?

 

I suppose if you wanted to do UV photography with actual collodion, there would be no need for an IR-blocker. UG1, UG11, or U-360 by themselves would work just fine. The pure iodide emulsions would be best. But it is unclear to me if that is being contemplated.

[Stefano]

If the collodion has no IR response, than you don't need to block IR.

[dabateman]

If the collodion has no IR response, than you don't need to block IR.

 

You don't need a filter with colloidal plates. We are trying to simulate the same image as the plates with our digital cameras because we don't all have chemistry labs in our garages.

[colinbm]

Sorry Toni

It is the AD200

http://www.godoxtech.com/godox-ad200-strobe-lighting/

[photoni]

Sorry Toni

It is the AD200

http://www.godoxtech...trobe-lighting/

 

Colinbm, I can't answer you, I don't know how flash godox work. I see from the site that they have two different light sources, fresnel and naked bulb. from my experience in collodion I see that the difference between transparent flash tubes and with a light UV (iridescent) layer is half diaphragm (I have never used Bowens with very yellow tubes). in the search for UV light it is a much more restricted thing, the collodion sees approximately 325 to 510 nm.

I learned on this site (thanks) that the digital sensors seen a few above 350 and many above 1050 nm.

I'm sorry but I haven't been able to do a real test yet, I made other measurements, one of the 5 steps (lay, sensitization, exposure, development, fixing) that I use to take old photos is wrong

[colinbm]

Thanks Toni

[OlDoinyo]

Are you using just iodide in your collodion or are you adding bromide and/or chloride? I understand this affects what the spectral response curve turns out to be, and historically all sorts of variations have been tried.

[photoni]

Are you using just iodide in your collodion or are you adding bromide and/or chloride? I understand this affects what the spectral response curve turns out to be, and historically all sorts of variations have been tried.

 

this is a table of the "recipes" that I have collected

it is difficult to explain the differences in a nutshell. just a few changes are enough to change contrast, sensitivity, ripening time and speed

[dabateman]

Truely excellent series of images on your Flickr page.

The portraits really stand out.

Being lazy with developing, have a black bag, chemicals, chemistry degree, flasks and bottles. Still haven't developed any of my 120 film. So I doubt I would go into wet plate.

Also enjoying the instax Fuji film. I should test it out for low resolution "colloidal like" images. I may have a filter that works and its sensitive down to deep UV.

[photoni]

Yesterday I finally did a good wet collodion on clear glass.

.

[OlDoinyo]

It looks like all of those recipes have some bromide, though the one labelled "Brian's New Gen" has the least (and would be expected to show the most UV bias.) I wonder why anyone would bother with the highly toxic cadmium salts when one can just use ammonium or potassium? I am sure there is also some reason why chloride was generally not used, as it is photosensitive.

[photoni]

I am sure there is also some reason why chloride was generally not used, as it is photosensitive.

 

I will ask this question to my teacher :)

 

mine is a collection of recipes. I only used 4 or 5. it takes a lot of practice, lots of photos and a great memory to know how to use them.

The most used are: - New Guy (with cadmium) because it is ready immediately if you have the iodizer already prepared just add collodion and ether and you can shoot immediately, or better the next day (it's faster and less contrast) ... it doesn't last a lot of time.

The most used recipe is Poe Boy, without ethere without cadmium. it takes 10 days to mature, then lasts 6 months, a year.

The fastest recipe, should be 2 iso, is the Reh, s New Gen with lithium, it has the drawback of very short-lasting.

[photoni]

Dear friends thank you.

Today I tried a photo with an apple and some "signal" flowers with wet collodion,

and Sony A7 full spectrum with BG39, (BG25 it doesn't work) and with BG25 + BG39 ...

this seems the best combination as you said .

Thanks so much.

Toni

[dabateman]

Excellent,

That looks very close. Do you like the uncoverted Nikon or the Sony best?

[photoni]

Excellent, That looks very close. Do you like the uncoverted Nikon or the Sony best?

 

It seems to me that Sony A7 full spectrum with BG25 + BG39 is more accurate. Nikon standard + BG25 is more extreme and contrasted.

Unfortunately I did not have time to do other tests the flowers in the apple were closing

[OlDoinyo]

It looks as if the lens on the plate camera is struggling to keep the whole frame in focus, which makes comparison more difficult. This may be due to the size of the camera--close-up DOF on a 4x5 camera can be a bear. But the apple in the collodion photo is definitely darker than in the digital emulation, and there are some other differences as well: some of the flowers appear darker in the upper shot.

 

Perhaps more distant test subjects would be easier, if you can devise such.

[ulf]

But the apple in the collodion photo is definitely darker than in the digital emulation, and there are some other differences as well: some of the flowers appear darker in the upper shot.

I think this is because the used filter stack transmit too much of the visual spectra and still think some thickness of UG5-type would work better, instead of the BG25.

[photoni]

It looks like all of those recipes have some bromide, though the one labelled "Brian's New Gen" has the least (and would be expected to show the most UV bias.) I wonder why anyone would bother with the highly toxic cadmium salts when one can just use ammonium or potassium? I am sure there is also some reason why chloride was generally not used, as it is photosensitive.

 

My teacher Giorgio Bordin (who wrote 2 books on antique prints and one on wet collodion) says: years ago chlorine was used for silver chloride contact printing (Kodak Azo) now it is used in POP processes (and then in contact). Photography typically uses iodine and bromine, both for negatives or positives in the camera, and for prints. In wet collodion, cadmium allows formulas that do not need to mature, while potassium makes them insoluble in alcohol, so everything is less immediate.

[photoni]

It looks as if the lens on the plate camera is struggling to keep the whole frame in focus, which makes comparison more difficult. This may be due to the size of the camera--close-up DOF on a 4x5 camera can be a bear. But the apple in the collodion photo is definitely darker than in the digital emulation, and there are some other differences as well: some of the flowers appear darker in the upper shot. Perhaps more distant test subjects would be easier, if you can devise such.

 

i used the smallest waterhouse i had for this lens (for more depth) + scary power. 4 times 10,000 watts.

I wanted UV sensitive subjects, not classic fruits or other flowers, the result is similar to an orthochromatic film.

Unfortunately I don't have friends with freckles, that would be the best test :)

[photoni]

I think this is because the used filter stack transmit too much of the visual spectra and still think some thickness of UG5-type would work better, instead of the BG25.

 

thanks. I'm undecided UG5 looks very short

[photoni]

How about this:

Sensor + BG3 (1.5 mm) + S8612 (2 mm), black curce, normalized.

 

But the sensor curve looks odd, let me check...

 

Yes, sorry, I added an extra zero in a few places, fixed. This is as before, but the correct version:

 

Still not bad.

 

Stefano, it's probably as you say, Sensor + BG3 (1.5 mm) + S8612 (2 mm), black curve, normalized.

[photoni]

Just did a quick experiment in the garden. Three filter setups, i) Schott S8612 1.5mm with Baader UV/IR cut (similar to internal filtration on normal unmodified camera), ii) Schott S8612 1.5mm plus BG25 3mm, iii) Schott S8612 1.5mm plus 1.5mm ZWB3.

 

Photos taken on a multispectrally modified Canon EOS 5DSR, with a 40mm f.28 pancake lens. Settings f8, and ISO800 for all. Images saved as JPEG in camera, and then desaturated and auto contrasted in Photoshop before shrinking for sharing.

 

1. 'Visible' light, S8612 (1.5mm) plus Baader UV/IR filter

 

2. BG25 (3mm) plus S8612 (1.5mm)

 

3. ZWB3 (1.5mm) plus S8612 (1.5mm)

 

The BG25 does look different to the 'visible' one, with softer shadows and a lightening of the sky. The magnolia buds in the tree on the left also look darker. There is a bit of a difference between the BG25 and ZWB3 one, but more subtle. I do admit it was a quick and dirty experiment though, so take from it what you will.

 

I think your tests are too different from the photos I would like to take (people and flowers). thank you very much