Other glass plates

Ilford R.40 Rapid Process Panchromatic glass plate

As well as the Selochrome stereo plates written about in my last post, I have also shot a number of different plates for night photography in recent months. I've used the last of the large format Selochrome plates written about in 2014 with some good results. Also mentioned in that blogpost were the Wratten & Wainwright Metallographic plates which were heavily fogged around the edges, so much so that I had all but written off using the plates. However, as I'd had a couple sitting in a plateholder for months, I decided to expose one on the same night as exposing this image on one of the Selochrome plates, and giving a moderately long exposure provided an image far less obscured by the fogging around the edges than I'd previously experienced.

Kodak Wratten & Wainwright Metallographic plate

As the Wratten & Wainwright box was sealed when I got it, I don't have a good theory as to why the plates shot recently should be less fogged than the others, except perhaps the fact that these plates would be from the central portion of the box, with a number of plates stacked on top (and below) the two illustrated here - although the edges of the plates themselves remain in the same relation to the edges of the box as those at the top or bottom of the stack.

Wratten & Wainwright glass plate

Incidentally both plates shown here exhibit true solarisation - the brightest highlights in the streetlamps have turned black. The term solarisation (when not describing a digital filter) is usually applied to what is more properly known as the Sabatier effect: the exposure in these highlight areas is such that the negative begins to lose density beyond the shoulder section of the characteristic curve (this phenomenon gets a brief mention in Ansel Adams' The Negative when describing his photograph The "Black Sun", Owens Valley, California). There's still a fair amount of fogging, and exposing for longer to combat this has resulted in what appears to be grain seen in the highlight areas, but this is scanner noise caused by the high density.

Late last year, I found two boxes of 4x5 inch plates, both Ilford R.40 Rapid Process Panchromatic - one box had been previously opened, but then resealed with black tape, and no plates had been used from it. I opened the other box for the information leaflet inside, which provided a date - August 1959.

Ilford R.40 Rapid Process Panchromatic glass plates

As described in the Ilford Manual of Photography (1946), Rapid Process Panchromatic plates were "For copying coloured originals. A plate of high contrast. The standard plate for colour separation screen negatives for photo-lithography." These were fifth highest in the list of plates by contrast in the Manual, and, as a process plate, it isn't given a speed: these plates were not intended for pictorial photography. The word Rapid in the name refers I think more to the speed of development rather than sensitivity - the information leaflet with the plates gives a development time of 2 1/2 minutes in ID13. The plates were introduced in 1918, and, according to Silver By The Ton, were rated 8 ASA in the post-1960 standard: other plates with the term Rapid in the name around the same time were rated 20 ASA.

Ilford R.40 Rapid Process Panchromatic test plate

For a test exposure, I rated one plate with an exposure index of 10 as a reasonable starting point, and with three successive exposures by progressively withdrawing the dark slide, gave the plate effective exposure indices of 10, 5, and 2.5 from right to left in the shot above. This was stand developed in RO9 One Shot, diluted 1+150 (to reduce contrast) for one hour. The results were very encouraging. The central section, with an effective rating of 5, looked best from the test plate. However, when shooting them at night, the first set of plates did appear to be overexposed, not helped by using a developer dilution of 1+100, rather than 1+150. The highlights in these negatives are very dense, and this again added noise when scanning in these areas, much like the Wratten & Wainwright plates: the image at the top of this post is one of the plates shot and developed in this fashion. I reduced my exposure times for the next shots by around one stop, and developed these plates at 1+150, as below.

Ilford R.40 Rapid Process Panchromatic plate

The Rapid Process Panchromatic plates are amongst the best I've used, in terms of the emulsion showing very little age-related deterioration; when coupled with getting the exposure right and developing to reduce the inherent contrast, the plates produce excellent results.

Ilford R.40 Rapid Process Panchromatic plate

Special Rapid Panchromatic plates

I've also recently used some quarter-plate size Special Rapid Panchromatic plates. First produced in 1919 at 32 ASA, these are "Fine grain. Fairly high contrast. General purpose plate. Widely used in scientific; and in the photo-mechanical trade for block making, offset work and photogravure." These are just above the middle of the contrast range of Ilford plates at the time. A leaflet inside the box was dated to 1946.

Special Rapid Panchromatic plate test

Rather than shooting these plates for the ongoing night photography project, I used most of the plates from the box on the LAPC photo walk last month; these were just fast enough to use handheld, rated around 10. The test plate above was also rated 10: with three successive exposures, the middle section at an exposure index of 5 provides a fuller negative. The plate below was one that I did shoot at night with a twenty-minute exposure which captured people queuing at a bar better than expected, if still very faint.

Special Rapid Panchromatic plate

Some time around 1950 Ilford's plate names gained prefixes with a letter and numerals: the Special Rapid Panchromatic above were later given the prefix R.20 as seen on this leaflet. I've wondered for some time about how these were constructed, what was the logic to them. The Hypersensitive Panchromatic and Fine Grain Panchromatic emulsions, being new just before the second world war, were not abbreviated in same way as other emulsions later: these were already abbreviated to HP and FP while the films went through their numerical iterations. Most other plates were given the alphabetical prefixes R, G and N (although not all - Selochrome didn't gain a prefix, but this was more of a brand name than a descriptor). Looking at the spectral sensitivity of the plates, as all panchromatic plates are given an R, it would appear that the letter are R denotes red sensitive; G plates are 'highly orthochromatic' with sensitivity extended into the yellow part of the spectrum that perhaps G is for green sensitive; and N for 'ordinary' plates would possibly mean not colour sensitive. I haven't found a logic to the numbers. One wonders if photographers stopped calling Soft Gradation Panchromatic plates that, and started referring to them simply as R.10 plates?

References
The Negative, Ansel Adams, 1981
Silver By The Ton, RJ Hercock and GA Jones,1979
The Ilford Manual of Photography, James Mitchell (ed.), 1946

Recent Glass Plate Work - part one

Electricity Substation, MPP Micro-Technical Mk VI, Ilford G.30 Chromatic Plate

Having had some success with using a number of different types of vintage glass plates, I wanted to design a project to use them for. These glass plates are a finite resource, although they do appear frequently in online auctions (photographic plates are still manufactured, but only for very specialist applications, and are prohibitively expensive). So, to use those plates I've already collected, I decided to undertake an ongoing project of urban night photography. There are a couple of examples in my post on Ilford G.30 plates, although it was only when photographing the disused cinema that the idea began to formulate.

Mimosa Porträtyp-Antihalo plate test

With the exception of the Ilford G.30 plates, most of the plates I've used are from previously opened boxes, which does mean that there is a chance that contents may have been exposed to light at some stage in their history. This has only been the case with the Mimosa Porträtyp-Antihalo and Kodak B 40 plates, and it hasn't been all of the plates in the box. The Mimosa plates have nothing to date them securely, but these could be as old as 1930s-40s (the box says these are "Made in Germany" and presumably date from before East and West Germany). I shot a test of these, which did come out with heavy fogging, and a number of Kodak plates. I have been systematically testing the plates in my Icarette L with successive exposures to a get a rough idea of the exposure needed.

Kodak B 40 Fine-Grain Regular plate test

Kodak B.4 Half-Tone plate test

Some of the plates were originally for specialist applications, such as the Kodak B.4 Half-Tone plates, which as the name suggests, are high-contrast; many of the plates are not panchromatic, meaning that they can be loaded under a safelight, useful when there are loose plates in a box, making it easier t to determine which is the emulsion side. The safelight for the B.4 Half-Tone plates is given as 'OB'. Although OB doesn't appear on Kodak's safelight data sheet, all the other 'O' series safelights are yellow. Considering the given safelight for these plates would be yellow, I made a guess that these are blue-sensitive only and loaded the plate under a red safelight. (Given my limited experience of different Kodak plates, panchromatic plates have a 'P' prefix, orthochromatic, 'O', so it would make sense for blue-sensitive to have 'B' - although I have found nothing to confirm this).

Kodak P 300 Special Rapid Panchromatic and P.1600 Panchro-Royal plates

Two previously unopened boxes of plates I've made tests from are Kodak P 300 Special Rapid Panchromatic and P.1600 Panchro-Royal plates. As sealed boxes, these have information sheets inside, useful for the original meter settings and developing times: I've posted the P 300 Special Rapid Panchromatic sheet and the P.1600 Panchro-Royal sheet on Flickr. I've generally been using a starting point of increasing the exposure by 1 or 2 stops for the tests to compensate for the age of the plates, then the succesive exposures provide a more accurate exposure index to shoot with. Although both boxes were sealed, the Panchro-Royal plates have not aged as well as the Special Rapid plates, which are 'tropically hardened': this may or may not have an effect on the longevity of the emulsion.

Kodak P 300 Special Rapid Panchromatic plate test

Kodak P.1600 Panchro-Royal plate test

Shooting them at night adds an extra layer of difficulty and not only in terms of getting the exposure right (I haven't touched on reciprocity law failure). The shot of the ghost train below proved hard to focus, even with the lens wide open at f4.5: the image on the ground glass screen was very dull, simply because the scene was at a considerable distance from any streetlights. Stopping down to f5.6, I calculated a ten minute exposure. Using a smaller aperture with greater depth of field would have meant that the accuracy of focus would be less critical, but this would have given much longer exposure times. The 4x5 G.30 Chromatic glass plates (shot with my MPP Micro-Technical Mk VI camera) are still the best plates I've used, and both subjects using them on this post were well-lit, in terms of night photography.

Branches and Shadows,  MPP Micro-Technical Mk VI, Ilford G.30 Chromatic plate

Concrete Stairwell, Wallace Heaton Zodel with Kodak O.250 plate

Ghost Train, Ica Icarette L with Kodak O.250 plate