D76 1:1 TM100 EI 100 = 9.5min / EI 64 = 12min. With EI 64 time cannot be longer than with 100. Something wrong on that table or on me. Some explanation ? Tks.
There is always "something" wrong with that table. ;-)I suppose there is something wrong on that table.
for d23 i use 10% extra time of d76, idk if my math is correct but i calculate 10% of the d76 time and add that to the top. so for kentmere 400 its at 9.5 minutes d76 stock, 10% of 9.5 is 0.95 (i rounded up to 1) so my d23 time for d23 stock is 10:30 min. i found when printing this gives me roughly the same amount of density and detail from d76 (at least to my eye, i dont have those densimeters or whatever its called)¨runs,
I don't use D76, I am Beutler and D23 user. But independently of that I suppose there is something wrong on that table.
The use of D76 in a home darkroom setting is not associated with any particular or significant health or environmental problems, as long as basic precautions are taken (i.e. don't breathe or ingest the developer). What concerns there may be, trace down to three ingredients in particular; hydroquinone, metol and the borate buffer used in classic D76 to maintain desired pH. The hydroquinone is in itself toxic, but you'd have to eat an entire bag of D76 powder to die from it. Metol has been associated with skin sensitization; the epidemiology is rather unclear, but as always with photochemicals (also the 'eco' ones!) skin contact is to be avoided in principle. Acute toxicity of metol is even lower than hydroquinone. The borate buffer has become a concern more recently due to suspicions of risk to the human reproductive system. Again, avoiding ingestion of the developer suffices to make this risk manageable. Note that the concentration of all these materials in a working strength photographic developer is fairly low.there are better developers, also far better for your health and for the environment than D76
Besides, these days there are better developers, also far better for your health and for the environment than D76, which was never my choice, certainly not for T-Max.
XT-3 is what I use, a variant of X-tol. The two don't differ in result, but I like XT-3 because there's no dust coming up when preparing the stock solution.what developer better for one's health and environment do you use?
That is not only personal, although X-tol has many followers, but has also to do with your own equipment and habits of processing, as @250swb pointed out above. My aversion against D76 is personal too and based on own experience and work from fellows.is it really better?
The use of D76 in a home darkroom setting is not associated with any particular or significant health or environmental problems, as long as basic precautions are taken (i.e. don't breathe or ingest the developer). What concerns there may be, trace down to three ingredients in particular; hydroquinone, metol and the borate buffer used in classic D76 to maintain desired pH. The hydroquinone is in itself toxic, but you'd have to eat an entire bag of D76 powder to die from it. Metol has been associated with skin sensitization; the epidemiology is rather unclear, but as always with photochemicals (also the 'eco' ones!) skin contact is to be avoided in principle. Acute toxicity of metol is even lower than hydroquinone. The borate buffer has become a concern more recently due to suspicions of risk to the human reproductive system. Again, avoiding ingestion of the developer suffices to make this risk manageable. Note that the concentration of all these materials in a working strength photographic developer is fairly low.
Environmental risks are likewise marginal for a home setting in which maybe a few liters of D76 are used on an annual basis. In case the developer is dumped down the drain, the developing agents oxidize in the sewage system and further break down downstream. They're unlikely to end up in the environment in a recognizable or harmful form and concentration. The boron remains boron (although how it's organically bound may change), but here, the effect of dilution renders it virtually harmless. Does that make it good practice to chuck the developer down the drain? That's debatable; arguably, only zero emission is permissible. But then again, if you take your spent developer in a jug to a waste disposal facility, you'd at least have to go by bike and not by car to also hit the (almost) zero emission point. It then remains to be seen how the disposal facility deals with your waste and what kind of impact results from it.
For eco-developers (generally based on a phenidone/ascorbate system with something like a carbonate buffer), the environmental impact of discharge into sewage may be less (tiny compared to very very small for a private user). What we don't know, however, is the complete LCA (life cycle analysis) for the product and since the difference in effects downstream are likely small, upstream differences (in manufacturing, packaging, logistics etc.) may easily tilt the balance.
The long & short of it is that it's really, really difficult to say anything reliable about H&S impacts of a developer in a typical home use setting. As always, this is under the assumption that the user takes reasonable precautions to not ingest the chemistry, not get it into contact with mucous membranes (eyes etc) and to clean up spills & splashes.
The story may be different if you're running a commercial lab or community lab that sees intensive use. Both the usage and waste disposal patterns involved are different from a home use setting and more easily bring into view a somewhat thorough analysis of the products used and waste management practices.
The best solution from a H&S perspective is of course to avoid any darkroom work altogether. Since I think we can agree that this is not necessarily preferable within our community, I think the conclusion will always be that we have to strike a sensible compromise, taking the factors into account that we can oversee reasonably well. I personally would want to caution against dogmatically focusing on one or two factors, or crass generalizations based on vague assumptions.
XT-3 is what I use, a variant of X-tol. The two don't differ in result, but I like XT-3 because there's no dust coming up when preparing the stock solution.
That is not only personal, although X-tol has many followers, but has also to do with your own equipment and habits of processing, as @250swb pointed out above. My aversion against D76 is personal too and based on own experience and work from fellows.
Are you sure pouring fixer down the drain does no harm? This is exactly the opposite what experts [cousins and best friends are environmental and water scientists] and other best friends who destroyed their septic system told me.Long story short. The official requirements for disposal of photographic chemistry are mostly made with commercil users in mind. In most cases, the environmental impact of even pouring yout used fixer down the drain is negligible. It is often illegal though, but frankly, driving to the hazmat collection point pollutes the environment more, and it is probably not even treated any way in many cases.
Fixer is relatively easy to desilver for the most part. It also makes a difference whether you're a high-volume printer doing multiple sessions a week, or occasionally print a couple of 8x10's. And it does indeed make a difference whether you're on a septic tank or a municipal sewage system.Are you sure pouring fixer down the drain does no harm? This is exactly the opposite what experts [cousins and best friends are environmental and water scientists] and other best friends who destroyed their septic system told me.
Fixer is relatively easy to desilver for the most part. It also makes a difference whether you're a high-volume printer doing multiple sessions a week, or occasionally print a couple of 8x10's. And it does indeed make a difference whether you're on a septic tank or a municipal sewage system.
Environmental scientists will generally adhere to the principle that the only permissible discharge is zero discharge. The water will remain clean as we drive our SUV's and F150's to the local disposal station where our used fixer can be incinerated by chucking hydorcarbons onto it and setting it alight - or simply dumping it in a 'designated place'.
D76 1:1 TM100 EI 100 = 9.5min / EI 64 = 12min. With EI 64 time cannot be longer than with 100. Something wrong on that table or on me. Some explanation ? Tks.
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