n_dhananjay3

Thanks for the reply, Ed. The stock was prepared maybe 2 months ago

(with fresh glycin) and the working solution was mixed just before

processing. I'm inclined to rule out oxidized developer in the stock

because I made some working solution about a week earlier to develop

some regular film and it worked fine. Also, the edges of the film

(which had received absolutely no exposure) did not show any stain.

I'm guessing oxidized developer would have led to general (i.e., not

image specific) stain much like fog. Cheers, DJ.

I've been experimenting with getting pictorial gradation from lith film using various developers. The other day I used the metol-glycin FX2 (but it uses metaborate instead of carbonate as the alkali). The film has a curious yellow-orange stain. My first thought was aeriel fog but the unexposed edges of the film (which were covered by the sheet film holder) were clear without any trace of the stain. I haven't actually printed any of the negatives yet to see if the stain is proportional to density (and lack a color densitometer to see if that is the case). But I'm curious as to whats happening with the chemistry here - I'm pretty sure glycin is supposed to be a pretty clean working developer and resistant to aeriel fog. I've used diluted D23 (metol based) before and that was pretty clean. Any hunches what I'm seeing here? Thank. DJ

When split toning, you need to do Selenium first, followed by gold. I

believe this is because the toners work in different ways. Selenium

works by replacing the silver while gold tones by coating them with a

colloid of gold. So the color with gold toning is a rsult of the

silver seen through the gold colloid. Selenium toner has the ability

to get past the colloid and change the colour of the silver halide

molecule beneath, a change visible through the colloid. Cheers, DJ.

I can't be positive about this but I think translites are the film

used to make the backlit displays one sees in airports etc. The

cloudiness is probably due to the age. DJ

As noted above, lots of folks (Ilford, Anchell & Troop) recommend

against a prewet since most modern films have stuff incorporated to

promote even wetting etc. Phil Davies reported some tests he had done

where a prewet did influence development, but did so in different

ways with different films. It increased contrast on some film-

developer combinations while decreasing it on others. So, as

suggested above, if it ain't broke, don't fix it. If you do want to

try a prewet, you will need to test your film-developer combiation to

see what the influence of a prewet is. Good luck, DJ.

With re to Andrea's question, the problem is not solved in BTZS type

tubes. The neg comes out of the tubes looking blotchy because the

anti halation backing is not completely removed. It comes off in the

fix i.e., the negatives are fixed in a tray. Have also heard a long

wash can fix it. Among the drum style processors, the Unidrums are

nice because they have ribs which hold the film away from the walls

and permit the anti halation backing to removed in normal processing.

Cheers, DJ.

I've used an aquarium heater stuck in the tray. I guess ideally you

would want a pump to circulate the water around - I just used to

swirl the water around with my hand. Check out agricultural supplies -

some of them make tray heaters that basically look like mats which

does sound perfect(e.g., http://www.ken-bar.com/gardener.html). You

might want to make sure that is safe around water, though (although

one would think that it should be given that plants get watered).

Hope this helps. Cheers, DJ.

It helps to use a strong monochromatic filter when using the lens in

its converted form. That's because you lose some correction when you

remove the front element and using a strong monochromatic filter can

reduce the chromatic aberrations. Cheers, DJ.

I have to agree with Robert's comments about maximum black. It is

often recommended that testing for the exposure scale of a paper

should entail 0.04 above base+fog of paper for Dmin and 90% of Dmax

(see, for e.g., Phil Davies 'Beyond the Zone System). There are

plenty of good reasons for this. Foremeost is that it keeps you off

the shoulder of the curve of the paper. Otherwise, you are combining

the low contrast shadow portion on the negative with the low contrast

shoulder of the paper and you are going to end up with terribly low

local contrast in the shadows. What you want is something that looks

convincingly black. Maximum black of a paper is a sensitometric

quantity you want to know but it need not be an expressive one. After

all, if you use a paper with a high Dmax (2.1 or so) and work with

the 90% figure (i.e., 1.9), you end up with a shadow density on your

print that can be higher than using the maximum black on a paper with

a low Dmax (for e.g., a matt surface). A convincing black is as much

a function of other elements such as what the sorrounding tones on

the print are etc. Other techniques like the use of a compensating

developer to increase the local contrast in the shadows can also

help. However, it is probably a good idea to stay off the shoulder of

most modern papers, which anyway offer fairly high Dmax values. Hope

this is helpful. DJ

Actually, in photography, it IS correct to say that diffraction only

depends on f stop. Diffraction IS a function of the physical

size of the aperture. However, diffraction patterns are angular

patterns and are thus also a function of how far the

aperture is from the screen used to view the diffraction pattern

(i.e., the film). Note that a shorter lens is closer to the film than

a longer lens. So even though the shorter lens has a smaller physical

size of the aperture (greater diffraction), it is closer to the film

and the diffraction pattern spreads less than it would with a longer

lens which is further away from the film. So, in photography, it is

absolutely accurate to say that the diffraction pattern is determined

only by the f stop. Cheers, DJ.

The Jobo product is Protectan, I think. You could also use nitrogen

from your nitrogen burst tank (if thats your choice of agitation).

Carbon di oxide might be the one thing I would be a little leery of

since it can combine with water to form carbonic acid, which can

affect the pH of the developer, but these are probably baroque

worries. Good luck. DJ

Yes, develop, stop, fix. Re high contrast, I don't know what format

etc you plan to work on. Tech Pan or other document films should work.

If you work in large formats, you could try lith film developed in

lith developer. Or enlarge smaller formats onto lith film. Good luck,

DJ.

Don't know about downloadable versions You can always try

www.craigcamera for a manual. Good luck. DJ

Certainly stay away from times below 5 minutes. Yes, you can dilute

the developer and use the same time. Just how much to dilute it can

only be determined by testing. But what you are suggesting sounds in

the ballpark.

 

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Prewets will affect the devlopment time, but it sounds like they do so

erratically. Phil Davies reported some tests where different

film/developer combinations responded in differing ways to a prewet.

Some manufacturers (e.g., Ilford) recommend against a prewet since

they incorporate agents into the film to promote even wetting etc.

Again, only testing can answer the specific question, but when I

tested a 5 minute prewet of TriX with HC110, it needed a slightly

longer development time (approximately 20% or so longer). Good luck.

DJ

Dunno... It is also possible that the fresnel is basically taking the

collimated light coming out of the condensors and directing it

towards the edges (exactly, the way it does with a ground glass). In

other words, it is un-collimating the light and making it diffuse.

Just a thought. DJ

Thank you for the responses. Isn't Phenidone supposed to be a bugger

to dissolve? Is it possible to dissolve 10gms in 100ml? Pete, I'll

get in touch with you offline for specific formulae. Cheers, DJ.

Just a note to add to the previous post. Strictly speaking,

diffraction is a function of aperture size or the physical size of

the hole and that is how it would be defined in a physics textbook.

Which means that the larger area aperture in a 300mm lens at f/16 (as

compared to a 50mm lens at f/16) should provide lower diffraction.

However, diffraction patterns are angular patterns and as such are

dependent on how far from the aperture you place the screen used to

view it also. In photography, the aperture is at the optical center of

the lens and the screen is (for infinity focus) one focal length away.

The physical size of the diffraction blur is then the focal length

divided by the apparent size of the aperture i.e., the definition of

the f stop. Thus, in photography, diffraction is only a function of f

stop and not a function of the focal length. In simpler terms, the

larger aperture of the 300mm lens does offer lesser diffraction at the

diaphragm (i.e., less bending around the diaphragm) but since the

light now has a longer distance to travel (as compared to the 50mm

lens), the smaller bending still results in a fair bit of blur at the

viewing screen. Sorry to be pedantic but... We now return you to your

regularly scheduled program. Cheers, DJ.

Hi, I'm thinking of trying a couple of formulas that need phenidone. I lack the ability to measure out small amounts (tenths of a gram) accurately and was thinking of replacing the phenidone with metol (about 10 times the amount). Would appreciate any pointers based on experience. I'm willing to live with the speed loss of metol vis-a-vis phenidone but anyting else to look out for. Thanks, DJ.

I remember Kachel mentioning (maybe in Darkroom Techniques) that

color of light does influence an emulsions response. A traditional

emulsion gains contrast when exposed with strong red light, (as when

exposed through a 25 red filter), which is what I found in my tests

and, if memory is serving me right, new technology films lose

contrast. Might be worth keeping in mind if you're exposing under a

color head. Good luck. DJ

If the problem you are having is that the high zones are placed close

together, this is probably because the bulb is parallel to the board.

Illumination falls off as the square of the distance and it is hardly

surprising that the lower zones (further away from the light) are

further apart than the higher zones (closer to the light). You should

be able to increase the spread on the 'zone board' by moving the

paint can containing the lamp so that it shines on the board at a

slight angle instead of being almost parallel to it. However, that

might reduce the total range of zones on the same length of the board

also. Hope this helps. DJ

I once dropped a holder in the snow and found that the neg had a

blotched area at the corner where the dark slide must have dragged

some flakes in. So, given it was cold, I guess it is possible that

there were ice crystals that formed on the negative. The other

possible explanation that I could think of is that maybe the ice

crystals somehow messed up removal of the anti halation backing

(isn't TMX/TMY supposed to have a pretty stubborn coating) - I'm

wondering because you say it has a cool cast and the coating is sort

of purplish, right? Might be worth taking some PEC12 or neg cleaner

to them or even checking to see if the spots actually print. Good

luck. DJ

Yes, it can be repaired - a camera repair shop should have something

that looks like a plier with a curved clamping end. Clamp around the

filter threads and gently squeeze back into shape - sorry for the

incoherent description - wish I knew what the tool was called. Good

luck. DJ

Isn't what you get on film a combination of lens and film resolution.

If its a lens test you want to do, I suspect you need to examine the

aeriel image. If that's not possible, I would second Sean's

suggeestion of Tech Pan - the ceiling should be high enough to yield

better data than other films with lower resolution. Good luck. DJ

Enjoy the camera. At f/8 or f/11, they provide wonderful pictures.

Check home.att.net/~j..harper/front.html for more details about the

YashicaMats. Cheers, DJ.

Try contacting Midwest Photo Exchange (www.mpex.com). I think they

manufacture these masks. Worth checking out. Cheers, DJ.