If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#1
|
|||
|
|||
a mild bleach
Ugh... it seem the last batch of prints I did was on a somewhat too old
paper .... I've since cleaned up the whites be increasing the restrainer, but I'm still left with a number of prints with slightly grey whites. Can anyone recommend a mild bleach I could use to clean them up? Thanks. |
#2
|
|||
|
|||
a mild bleach
"Lew" wrote in message ... Ugh... it seem the last batch of prints I did was on a somewhat too old paper .... I've since cleaned up the whites be increasing the restrainer, but I'm still left with a number of prints with slightly grey whites. Can anyone recommend a mild bleach I could use to clean them up? Thanks. I aggee with the fellow who suggested checking you safelight. However. It is possible to clear highlights with a mild Farmer's Reducer used with mixed bleach and fixer. This tends to clear low density areas faster than higher densities. When used separately the reducer is more even in action but you want to clear the highlights here with as little effect as possible on the mid-tones and shadows. Farmer's used to be available in packaged form from Kodak and may still be from some other suppliers such as Freestyle Photo. Its easy to make, the formula follows. Potassium ferricyanide is relatively safe. The cyanide part is very strongly bound and requires high heat or strong acid to release cyanide gas. It may be considered a hazardous material which may make it hard to obtain. Kodak R4a Stock Solution A Potassium ferricyanide 37.5 grams Water to Make 500.0 ml Stock Solution B Sodium thiosulfate (crystalline) 480.0 grams Water to make 2.0 liters To use take Stock Solution A 30.0 ml and Stock Solution B 120.0 ml Add water to make 1.0 liter. Pour the mixture immediately over the negative. Watch closely. When it has been reduced sufficiently wash thoroughly. I suggest re-fixing and re-washing after reduction to insure that there are not halides left in the emulsion which can eventually cause staining or fading. The above is given for negatives, which require a stronger reducer than prints. You can dilute the reducer to make it slower and more suitable for prings. You can also "paint" the surface where you want to have reduction. There are other reducers but their ingredients may be more difficult to obtain. A good reducer for spotting is iodine in solution. This is a very powerful reducer although it can be high diluted. Since it converts the silver to silver iodide, which is difficult to fix out the prints should be treated in a film strength "rapid" fixer (ammonium thiosulfate) after reduction. A very mild reducer, one suggested mostly for removing dichroic fog, which is a deposit of very finely devided silver on the surface of a print or negative is a mixture of film strength _acid_ rapid fixer with about 15 grams per liter of citric acid added. This may suffice to clear slightly veiled highlights. Film or prints so treates should be re-fixed and washed. -- -- Richard Knoppow Los Angeles, CA, USA |
#3
|
|||
|
|||
a mild bleach
.... this is definitely fog & old age. As I originally posted, other papers
process just fine & the problem for this paper is cleared up by adding restrainer. Do you have any experience cleaning up highlights by bleaching? .. "Peter" wrote in message ... On Feb 16, 7:50 pm, "Lew" wrote: Ugh... it seem the last batch of prints I did was on a somewhat too old paper .... I've since cleaned up the whites be increasing the restrainer, but I'm still left with a number of prints with slightly grey whites. Can anyone recommend a mild bleach I could use to clean them up? Thanks. Did you check your safelight? |
#4
|
|||
|
|||
a mild bleach
Sodium thiosulfate (crystalline)
Is this the same as Pentahydrate? "Richard Knoppow" wrote in message m... "Lew" wrote in message ... Ugh... it seem the last batch of prints I did was on a somewhat too old paper .... I've since cleaned up the whites be increasing the restrainer, but I'm still left with a number of prints with slightly grey whites. Can anyone recommend a mild bleach I could use to clean them up? Thanks. I aggee with the fellow who suggested checking you safelight. However. It is possible to clear highlights with a mild Farmer's Reducer used with mixed bleach and fixer. This tends to clear low density areas faster than higher densities. When used separately the reducer is more even in action but you want to clear the highlights here with as little effect as possible on the mid-tones and shadows. Farmer's used to be available in packaged form from Kodak and may still be from some other suppliers such as Freestyle Photo. Its easy to make, the formula follows. Potassium ferricyanide is relatively safe. The cyanide part is very strongly bound and requires high heat or strong acid to release cyanide gas. It may be considered a hazardous material which may make it hard to obtain. Kodak R4a Stock Solution A Potassium ferricyanide 37.5 grams Water to Make 500.0 ml Stock Solution B Sodium thiosulfate (crystalline) 480.0 grams Water to make 2.0 liters To use take Stock Solution A 30.0 ml and Stock Solution B 120.0 ml Add water to make 1.0 liter. Pour the mixture immediately over the negative. Watch closely. When it has been reduced sufficiently wash thoroughly. I suggest re-fixing and re-washing after reduction to insure that there are not halides left in the emulsion which can eventually cause staining or fading. The above is given for negatives, which require a stronger reducer than prints. You can dilute the reducer to make it slower and more suitable for prings. You can also "paint" the surface where you want to have reduction. There are other reducers but their ingredients may be more difficult to obtain. A good reducer for spotting is iodine in solution. This is a very powerful reducer although it can be high diluted. Since it converts the silver to silver iodide, which is difficult to fix out the prints should be treated in a film strength "rapid" fixer (ammonium thiosulfate) after reduction. A very mild reducer, one suggested mostly for removing dichroic fog, which is a deposit of very finely devided silver on the surface of a print or negative is a mixture of film strength _acid_ rapid fixer with about 15 grams per liter of citric acid added. This may suffice to clear slightly veiled highlights. Film or prints so treates should be re-fixed and washed. -- -- Richard Knoppow Los Angeles, CA, USA |
#5
|
|||
|
|||
a mild bleach
Lew wrote:
Ugh... it seem the last batch of prints I did was on a somewhat too old paper .... I've since cleaned up the whites be increasing the restrainer, but I'm still left with a number of prints with slightly grey whites. Can anyone recommend a mild bleach I could use to clean them up? Thanks. Ansel Adams gives the following bleach for prints to clear the highlights. I infer his use of this process was not to save old paper, but to arrange a little more detail in the highlights. Solution A Water (room temperature) 300 ml Potassium ferricyanide 62.5 gm Potassium metabisulfite 4.2 gm Water to make 500 ml Solution B Water (room temperature) 600 ml Ammonium thiocyanate 330 gm Potassium bromide 30 gm Water to make 1 l Mix 1 part of a, 2 parts of B and 10 to 15 parts of water. Immerse the dry print face up with vigogous agitation for 5 to 10 seconds. Place immediately in water and agitate until the bleaching solution has been removed from the surface of the print. Examine the print , and return it if necessary to the bleaching bath (advised only for a few seconds). If the print is wet initially, or if the solution is too dilute, the middle and the lower tones may respond to the action of the bleach, thereby weaking the print values in general. I advise being very careful with this or it will get away from you. -- .~. Jean-David Beyer Registered Linux User 85642. /V\ PGP-Key: 9A2FC99A Registered Machine 241939. /( )\ Shrewsbury, New Jersey http://counter.li.org ^^-^^ 07:55:01 up 26 days, 23:46, 3 users, load average: 4.27, 4.26, 4.14 |
#6
|
|||
|
|||
a mild bleach
Thanks, I've lost track of my Adam's books over the years.
"Jean-David Beyer" wrote in message ... Lew wrote: Ugh... it seem the last batch of prints I did was on a somewhat too old paper .... I've since cleaned up the whites be increasing the restrainer, but I'm still left with a number of prints with slightly grey whites. Can anyone recommend a mild bleach I could use to clean them up? Thanks. Ansel Adams gives the following bleach for prints to clear the highlights. I infer his use of this process was not to save old paper, but to arrange a little more detail in the highlights. Solution A Water (room temperature) 300 ml Potassium ferricyanide 62.5 gm Potassium metabisulfite 4.2 gm Water to make 500 ml Solution B Water (room temperature) 600 ml Ammonium thiocyanate 330 gm Potassium bromide 30 gm Water to make 1 l Mix 1 part of a, 2 parts of B and 10 to 15 parts of water. Immerse the dry print face up with vigogous agitation for 5 to 10 seconds. Place immediately in water and agitate until the bleaching solution has been removed from the surface of the print. Examine the print , and return it if necessary to the bleaching bath (advised only for a few seconds). If the print is wet initially, or if the solution is too dilute, the middle and the lower tones may respond to the action of the bleach, thereby weaking the print values in general. I advise being very careful with this or it will get away from you. -- .~. Jean-David Beyer Registered Linux User 85642. /V\ PGP-Key: 9A2FC99A Registered Machine 241939. /( )\ Shrewsbury, New Jersey http://counter.li.org ^^-^^ 07:55:01 up 26 days, 23:46, 3 users, load average: 4.27, 4.26, 4.14 |
#7
|
|||
|
|||
a mild bleach
"Lew" wrote in message ... Sodium thiosulfate (crystalline) Is this the same as Pentahydrate? Yes. Most of the older formulae calling for sodium thiosulfate specify the crystalline form. Modern packaged fixing baths, such as Kodak fixer, are the anhydrous form. The conversion factor is: Where crystalline is specified use 0.64x of the anhydrous form. Where anhydrous is specified use 1.57X the crystalline form. These are rounded off but sufficiently accurate for photographic work. -- -- Richard Knoppow Los Angeles WB6KBL |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
iodine bleach, selenium--cause unwanted split? | QueenAdelle via PhotoKB.com | In The Darkroom | 1 | October 31st 06 04:38 AM |
Does B&W bleach affect color emulsion? | Ed | In The Darkroom | 1 | June 29th 06 11:04 AM |
[mild OT] Looking for a photog site | Sk8_Or_Die! | Digital Photography | 1 | January 29th 06 12:42 AM |
[mild OT] Looking for a photog site | Sk8_Or_Die! | 35mm Photo Equipment | 1 | January 29th 06 12:42 AM |