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Photo Engineer
03-11-2011, 05:20 PM
I had not intended to do that. Believe it or not, it would take a lot of time and space in the book! :D There are too many ways to do things wrong!

PE

Ray Rogers
03-12-2011, 04:01 AM
I don't think any of this is unusual.
Teachers are often threatened by the progress of good students,
and many students often assume an aire of 'superiority'.

Has anyone missed this even here in our own little forum? ;)

Eder did a lot of early very detailed research ... and reported it.
The fact that Wall did not find a need for all those tidbits
says more about the progress of the field than anything else.

I have read Eder's work and I think I understand what Wall means.
On the other hand, Eder's work (and the BJOP for that matter) was their "internet".
For someone wanting a "cookie cutter", Eder has a lot of useless grains,
but for the researcher set on designing a different kind of cookie,
Eders work was like an encylopedia or todays internet...

While cookie cutting immitators may complain,
who is to say what will turn out to be of value to the creator thinking out of the box?

Wall has a point, but Eder was greater scientist and teacher.

Ray Rogers
03-12-2011, 04:58 AM
I am not going through each book with specifics directed to each formula... Thats enough said.

PE

Ah, yes, but I suggest that there is a good reason for that.
In the context of history, I don't think those men were so (fill in the correct word).

It is only natural for you to improve upon 50-80 year old texts.
However, I doubt you can live up to your claim and the appearent expectation of many on this fourm, of adaquately covering "modern" emulsion manufacture without stepping on Kodaks tail.

Anything Kodak OK's will not likely be new nor critical to their POV.

Or course, new to whom is the question.

Least you think I am being negative--- not at all.
I cannot think of anyone back here on Earth
more egar to see what you have to say
about your walk on the moon.

Best Wishes

Ray

Athiril
03-12-2011, 11:23 AM
I had not intended to do that. Believe it or not, it would take a lot of time and space in the book! :D There are too many ways to do things wrong!

PE

One could just get some of the other emulsion making books? Assuming they have photos.. :)

Photo Engineer
03-12-2011, 11:42 AM
Interestingly enough, none of the other texts I have been able to get show photos made with any of the emulsions. Mine will probably be a first where I show the emulsion formula, the grains, the sensitometry, the spectral sensitivity, and then show pictures compared to a commercial product.

PE

Ray Rogers
03-12-2011, 12:39 PM
I think that will be new and unique.

What do you see as the difference between the DIY product and the commercial product?
Do such products have no meaningful commercial edge?

I would think Ilford and others need as much support as they can get,
if we want them to be around much longer....

Photo Engineer
03-12-2011, 12:57 PM
Ray;

Commercial products have the potential for much higher overall quality. About 10% of all hand coatings using doctor blades usually have some defect of some sort, the remainder being of production quality. The defects can vary from small pinholes (retouchable) to non-uniform areas (non-retoucahble). Some are there but cannot be seen in the print. So, variability might be the bottom line here differentiating home coatings from production coatings.

You must remember though that Jim Browning made production quality coatings at home, albeit with a pricey machine, but it did work and did give excellent 30x40 sheets. And, we walked into his darkroom, started things up, melted gelatin and made a perfect film coating the first time. We did the same with paper after a day of experimentation as well.

So, high quality is possible.

PE

Ray Rogers
03-12-2011, 01:16 PM
I know.

But on the other hand, Jim ended up selling the machine to PF.
The machine appears not to have been put to much use,
and might even be up for sale again,
judging from posts I have seen on apug.

(BTW anyone know if there was a second or third commercial coating?
Jim mentioned it was about time in 2008 or so IIRC)

Photo Engineer
03-12-2011, 01:20 PM
Ray;

You are missing a point here.

A device that works on a personal basis will still work on a commercial basis, but if you consider the latter, you must consider the costs involved and the profits involved. In other words, the danged thing better pay off! If it is too labor intensive in a down market this does not mean it is a "bad machine" or even "up for sale". That is not for me to say anyhow. What I am saying is that it works but even so, the market may not exist at the current price/cost ratio. Just consider the cost of Silver Nitrate today!

PE

Ray Rogers
03-12-2011, 01:21 PM
What sort of problems might be present in a print that cannot be seen and why should it be of concern if it is not actually visable?

Ray Rogers
03-12-2011, 01:25 PM
Just consider the cost of Silver Nitrate today!

PE
Ok, Gotcha.

What do you pay for a pound these days?
Has it gone up that much?

Photo Engineer
03-12-2011, 02:08 PM
Well, I'll give you another specific example anyhow.

For production, you need LOTS of drying space to make a run worthwhile. For personal space you may need to only dry 1 or a dozen sheets. Drying space takes space that is dust, lint and chemical free and DARK for several hours. I can do that hands down here at home for my own needs of about 1 to 20 sheets per run, but doing it for 100 sheets or more would present me with a problem. Doing it for huge production type runs in large sheets would be a REAL problem!

And, it would have to be economical if you were to make any profit.

PE

Photo Engineer
03-12-2011, 02:10 PM
Ok, Gotcha.

What do you pay for a pound these days?
Has it gone up that much?

http://stores.photoformulary.com/Categories.bok or about $475 / #

JOSarff
03-12-2011, 03:31 PM
Photographs will examples of common mistakes would let the user realized that they are not alone and headed toward the right path.

Steve

Steve:

Photographs of good coatings would be betterI think. If yours doesn't look like that, something's wrong. Besides, Ron's book wil lhave something no other emulsion book has ever had, pictures of emulsions.

Joe

Athiril
03-12-2011, 03:55 PM
$22/10g here.. about 3x the cost of raw silver, over twice the cost as above ;(

Anyway, possible to dry quicker with an infrared lamp or circulated air?

Photo Engineer
03-12-2011, 04:37 PM
Athiril, any of that is possible as long as you have the space! That is critical. And it must be dark, dust free and lint free. So, assume that I coat 100 sheets of 30x40 film or paper, now where to put it and how high can I stack it. Well, it would stack from floor to ceiling in a 10 foot high room leaving about 1" between sheets for air to circulate. That isn't enough!

You guys are not thinking PRODUCTION and are not thinking PROFIT. You are thinking home DR work. Yeah, I can modify a room at great expense, make maybe 20 - 50 sheets at a time and hand cut them. Then I sell them for $1 / sheet and take a loss of about $10 / sheet in costs and labor.

PE

Athiril
03-13-2011, 02:36 PM
Given your other thread.. I was thinking 120 and 35mm (or even 16mm/S16mm). If it can dry quickly enough to be moved slowly and be collected onto a reel.

Friend bought a Super America 35 a while back and I was impressed with it enough to want one too.

Photo Engineer
03-13-2011, 03:12 PM
I'll leave the coating of anything narrower than 120 to someone else. I may not even get into 120. IDK yet as the support supply is not huge, at least for me.

PE

Athiril
03-13-2011, 03:14 PM
IIRC it's available off alibaba.. in huge quantity though. Same from Lucky Film, you can get bopet and acetate film

Photo Engineer
03-13-2011, 03:22 PM
Well, I'll make the point more strongly then!

Since defects go up rapidly as the format becomes smaller, I will limit myself to what can be coated in the home darkroom. I have already determined that 4x5 can be coated with good results wrt defect rate, and I may also run the test on 120, but knowing the difficulties inherent in coating anything narrower, I will not be doing it. That leaves out 35mm, 16mm and 8mm!

PE