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You ignored the advice about having energy at 450nm and below.
The bulb you linked to has no significant energy in that area. Therefore if you need to print or burn-in at grades 4 and 5 , it will...

Yes i think it came from the exposure being faster. Probably in Victorian times when lenses like the Petzval were introduced, and exposures could then be in seconds rather than minutes.

Actually there was a plot from Ilford. Here is the discussion -...

The answer seems to be 'No' , but I did query Ilford last year about this and got advice , posted in a previous thread. This where the 450nm and below comment comes from. I will try & find the thread...

If you're using MG paper, you need to make sure the LED bulb has a decent amount of energy at or below 450nm ( ie. deep blue & violet ). Otherwise you won't be able to get the harder grades when you...

Well it's not very small - otherwise I wouldn't have ditched conventional developers in 1999 and used PMK mainly since then.
However my comparison was only against my usual developer at that time,...

Picking up on what Interneg has just said.
I contend that the key difference in both mids and highlights in staining-developer negs is not about a difference in density , but that they are less...

I can't see how you can increase the contrast ( with a fixed light source colour/grade ) from a contact print situation, by going to any form of enlargement. Contact printing pretty much has the...

I should probably stop using the term 'Callier effect' in further explanations, because I am likely to be mis-using it. I think that Callier effect strictly refers to the loss of overall contrast in...

I'll try & explain what I mean. It may take a couple or three postings. I can't offer much in terms of proof or quantitative measured, this is qualitative from negs and prints, however I do have some...

My impression from what I printed in 1999 from conventional vs. PMK negs is that the reduction in Callier coefficient is very significant in terms of the rendition of higher values and specular...

Is there a connection between tanning and the Callier effect/coefficient, which was the subject I cited ?

Here's one i was reminded of last night : the depth of field of a 300mm lens at f/32 when focused on a scene about 12 feet away is SHOCKINGLY shallow !

MF can be almost as bad with certain cameras, although the monetary loss is lower.
I recently had a holiday on the coast in N.Wales with a friend.
I took 5 cameras, from a Canon DSLR through to a...

I know exactly how you feel. Fatigue is often a factor.

Michael, that little table you did earlier is v. interesting and food for thought. It looks sensible to try a more significant increase in the amounts of A and B on my next try, given how much...

And do these developers also reduce the grain-scatter ( Callier effect ) in upper mid-tones and highlights ?

Ah, I was thinking back to the way some of your discussions with DREW have developed, regarding staining developers.

I suspected that you would eventually turn against the subject, Michael.
Good that you are, however, warning us callow impressionable youths against the dangers of getting too tied up in staining...

Aside from the stain colour and its effect on density - which was part of the interest.
https://sandykingphotography.com/an-intro-to-pyro-staining-developers/

Hey Martin - not so fast - we had two days straight without any rain, at the weekend !



Back in 2005/2006 when I was a half-assed fell runner, I could beat the train going down, and was 5mins...

Thanks Michael, yes.
I'll have a good look at the numbers ref WD2D and WD2H and have another go with an 'educated guess' at what might work.
I will probably also try the experiment with PMK 'A'...

(Edit : this reply to Mark, not to Michael ) :

Oh I already did a print from one of the negs exposed with a slightly more concentrated mix.
It was fine, but the subject wasn't all that demanding...

OK I should clarify, the Zone 2 detail on the WD2H ones was nearly the same as the PMK ones, so i don't think there's a fundamental loss of speed; they just look under-developed.

OK. I haven't got a densitometer ( we used to have one at work but it's been retired ) .
I keep thinking about it but find it hard to justifiy approx £1000 for a current one with a blue channel...

Thanks for putting that together Michael.
I went part-way through something similar when I got the first results from WD2H.

I'm not sure I can agree with you that the sulphite-to-developer ratios...

Fine, I understand ; let's see if anyone else comments. I can do some maths in the near future and work out how to make a larger bottle of 'A' solution that adds more water, Metol and Pyrogallol but...

Alan, we must try and work on this problem - because I have over £20-worth of Pyrogallol locked up in that 250ml 'A' bottle !

Looking back at the formula, I can see that one of the differences...

Unfortunately no, not that I'm aware of. That's why optical shops use either a test plate ( sphere ) matched to the design radius, or nowadays, interferometers stationed in the shop.
You will just...

Nice shot, is that from Harlech ?

Well, I disagree, that sounds plausible for polishing with pitch ( grinding with fine grit would remove more ) if the glass is soda-lime eg. float glass.
ps. I've made about 6 telescope mirrors.
It...

Yes, you slide things onto them, and slide things off them ..... ;o)

No but seriously, here is a picture, they were made years ago from rough 3/4 ply, and refurbished by me recently, to paint the...

It's tough to remember back 30 years, but I owned a Tachihara 5x4" in the early 90's and it was very good. I don't remember any obvious shortcomings, but I sold it because I concluded that 6x9cm with...

You may find that Superpan 200 is a little cheaper ( it is in the UK ) and it is the same emulsion and probably same base.

What's the part about cell interchange ?
Have you got a link to the brochure ?

I must look into the Macro Sironar data, I had not realised that it might only be 6 elements. The Schneider's are.
The Apo El-Nikkor is 8 elements and the central doublets have a fluor-crown for...

Interesting, that suggests it's inferior to the Schneider Makro-Symmar 120.

Yes, these lenses ( also the Apo Macro Symmar HM and the Apo Macro Sironar ) are the same element count and very similar overall design to the rare Apo El-Nikkor lenses, albeit optimised for a lower...

Great - sounds like the macro Sironar will be perfect !

There's a 150mm G-Claron, it's slow, but should be good for 1:1 and almost up to 2x with your bellows.... not expensive.