2009-11-20

Black and White Film Developing Chemistry



These are home-brewd specialties.  Quick-acting Fixer and Film Developer concentrate.  Both unique.  And perhaps the only ones of their type available here in the Philippines.   The supply of such chemistry here is dwindling.  They are not that easy to source anymore. With these, we need not fear the possibility of losing developing chemicals should the firms which import or distribute them decide to quit doing so.

"PaRODINAL FILM DEVELOPER CONCENTRATE.




Our homebrew is derived from the formula first published on the net by Donald Qualls.  It's a Rodinal-type developer formula derived from paracetamol.  Paracetamol (acetaminophen) and Rodinal (1,4-para aminophenol) are cousins.  And through a process which involves alkaline hydrolisation, paracetamol is converted to para-aminophenol.

However, our paRodinal brew is different
.  It does not use the pill type paracetamol, so the solution comes out clean and clear of suspended detritus.  It also uses some ingredients listed in the original Agfa Rodinal formula; using Potassium Hydroxide instead of sodium hydroxide mentioned in the original Qualls formula.  Our paRodinal Brew also has anti-chelating and anti-fog components which are absent from the original one published on the net.

PaRodinal shares many of the traits the original Rodinal is known for.  Longevity, compensation, increased contour sharpness, and ease of use.

This developer is a "one-shot" type. It means that a working solution is diluted (from 1+25 to 1+200) from the concentrate.  With those small amounts, a 120 ml bottle can develop more than 20 rolls of 35mmX36 exp film.    One-shot also means that everytime the developer is used, its potency is assured.  Unlike stored working-strength developers like D76 where re-use always involves the question of how much time should be added each time it is reused to compensate for partial exhaustion.   "One shot" means mix the developer, use it, and then flush it down the drain.

Like Rodinal, PaRodinal also is stable and has a long storage life, when stored sealed in its container.  The concentrate, which starts clear, will darken until it is as dark as Coca-cola.  The darkening is no sign of deterioration.  The concentrate can sit for months, or maybe  years and still be excpected to work like when it was new.  Other Developers like D76 have to used within a month (three months maximum) before they totally become useless.

Dilutions determine how the negative comes out.  Low dilutions (like 1+25) develop shorter, and give higher contrast.  High dilutions (like 1+100) give longer developing times, higher contour sharpness and compensation.  High contour sharpness means there is an increase in apparent sharpness in the negative- the details look sharper. Compensation means that highlights don't block up and shadows catch up- less burned out whites and dead shadows in the print.

1+50 is the suggested dilution for general use.

PaRodinal is not a fine-grain developer.  Film grain will be seen as is.  Film developed in other types of developer like D76, which have high sodium sulphite content, will appear to finer grain.  The extra sulphite in the developer 'shaves' and eats away at the edge of the grain and make them appear continuous.  In the print, the absence of these edges make it look that the grain is smooth.  But this also reduces the sharpness in the finer details.  PaRodinal, like the original Rodinal instead develops honestly and shows the grain as it really is.  HIgher dilutions tend to make the grain look a bit finer.

This developer is used just like Rodinal.  The same times for any given dilution and temperature combination can be applied for the film in use.  This developer must be used at 20ºC.  It is not recommended to be used above 25ºC because the film's gelatine emulsions can swell and soften too much at higher temperatures.

"EXPRESS FIXER"



"Express" means that this fixer does its job faster than conventional fixers. It contains some ammonium thiosulphate. It fixes the film completely in about 5 to 7 minutes.  Some films will even fix at 2 minutes.

Fixing time is really double the clearing time.  So if an undeveloped strip clears in 1 minute, fixing time is 2 minutes.  A bit more time can be given to make sure that the film emulsion is properly hardened.  This fixer contains some hardener to harden the emulsion and make it more robust against abrasions, scratches, frilling, and swelling.  The last can make the emulsion crack and craze, which gives the film a pseudo grainy appearance.

Typically, Luckypan film will fix in about 3 minutes.  Five or six minutes is sufficient for Fuji Neopan 400.  T-grain films like Kodak Tmax or Ilford Delta will take longer because Tgrain emulsions really clear longer.

A litre of fixer will fix 25-30 rolls (less with Tgrain films).  Using an Acid Stop bath between developing and fixing will extend the life of the fixer.

This fixer is of the acid-hardening type. 












2009-11-04

Wanna See What's Inside a Canon P?

This camera was sent to me for repair.  The second(closing) blind of the shutter wasn't closing anymore. 




I suspected broken ribbons.  It could however be something else, so the camera had to be stripped to see what really happened..  Getting the Canon P out of its shell was surprisingly easy :D



Removing the four main screws on the outer shell, the selftimer lever assembly, the lens mount, and a couple more screws under it, will take the shell off.



One of the ribbons which pulled the second blind home had snapped.



Titanium foil was used by Canon for their model "P" and "7" RFs, in place of the usual rubber-coated cloth.  The titanium foil can wrinkle from fatigue.  Or in this case, stress from being stuck and then being pulled out to be mended.

The top of the camera is very complicated.  This scary looking part has the shutter speed controls, the wind/rewind clutch, frame counter, shutter release, and film advance/transport.



And this is the part which gives the floating framelines.  It's semi-silvered inside.



The broken ribbon was replaced with a new one.  The intact upper ribbon was unglued so that a new one can be patterned after it.  The shutter was no longer disassembled.  The ribbons were threaded through the rollers, attached to the lath, and the other end reglued to the outer roller. Stitched in red:



Under the camera is the complicated Canon RF flash sync circuit.  Disassembly not recommended!









2009-10-29

Industar-69 28mm

This lens was made for the half-frame Belarussian "Chaika" ("Чайка" = "Seagull") half-frame cameras.  The 2nd and 3rd models of the Chaika were designed to have removable lenses.  No one is sure why this was done -the first Chaika model had a fixed, non-detachable lens-, but I think it was to allow the lens to be used in an Enlarger for printing. 

The lens has the standard Leica M39 thread (LTM39) mount,  but the working distance (the focal plane to lens mount flange distance the lens is positioned which allows infinity focus) is not the the same.  Leica's is 28,8mm.  Chaika used something like 29 or so mm.  This extra millimetre or so prevents infinity focusing when the I-69 28mm lens is mounted on the Leica.


the "Индустар-69" 2,8/28mm mounted on a Leica IIIc




As the reader will note later, infinity focus is not the only, nor is it the greatest concern here.  Coverage, or the ability to focus an image large enough to fill the frame.  "Frame" here is relative- the standard 24 X 36mm, 'half-frame'(a.k.a. "single frame") 18 X 24mm, and the 23.7 x 15.6 mm APS-C size CCD of the Epson whose 1,5X factor makes it 'see' like a 42mm on standard 35.

The lens was modified by altering its focus movement.  Portions of the inner barrel were filed away to make the lens move further in to allow infinity focus.  The focusing scale on the barrel was also reset to synchronise it with the lens' focus.  The aperture mark no longer coincided at the new positions, so a new mark was made by putting a drop of red paint on the aperture adjusting ring.

The lens too, being originally meant for a non-RF coupled camera, will focus only by scale since it has no means of engaging with the RF cams of the camera.  Scale focusing with a 28mm isn't that hard- its greater DOF more than compensates for focusing errors.  Plus, the I-69 has three "snapshot" focus settings on its barrel: "Portrait", "Group", and Landscape".  How is this used?  Look through the finder and set the focus against the figure which resembles closest what was seen through the finder:



Just line up the figure against the pink triangle which corresponds to "how much" is seen in the viewfinder.


Focusing is often a trivial matter.  In many instances, leaving the scale at the "group shot" mark (the 3 metre mark) and using f/8 will deliver DOF with a range of 1,6 metres to infinity.

Since the I-69 was designed to cover the 18X24 frame, the IMAGE CIRCLE it produces will be much smaller- smaller than what 'full frame' needs, but sufficient for the smaller 'half-frame'.

On an APS frame, the corners already vignette.  Aside from losing coverage, the edges of the image circle also dims.  Here is what it does with the Epson R-D1s digital rangefinder camera:




Scale-focused/distance 'guess-timated' at 0,9 metre.  Full 2,8 aperture. 
The I-69 is a Tessar type lens, and produces a swirly blur when used at full aperture, for closeups.
The corners of the picture show significant vignetting.



If the smaller APS-C frame already shows vignetting, a full 35mm frame shows TOTAL DARKENING at the corners of the frame.  This, as well as the significant loss of definition at the threshold areas indicate that its image circle is too small for the 35mm format, but more than sufficient for the half-frame picture.



Same subject as above, but on a 24X36mm Leica frame.
The blue tinge stems from the unfiltered exposure of tungsten movie film in daylight.







Conclusions:  The significant vignetting prevents further use of the lens for 'serious' work on full frame 35.  However, it can be useful for experimental or whimsical applications.  

On the Epson R-D1s, it can be used as a scale-focus snapshot lens, with a 42mm view.  Using it at f/8, the vignetting is not to apparent in many situations. 

The lens would be a perfect "normal" focal length for the micro 4/3s cameras.  No modification is even necessary to adjust the focus.