902 Light Brown Safelight

[Ian-Barber]

Been given this box of unopened paper and on the box, it says Safelight 902 Light Brown.

Will this still be safe to use under a red light?

 

[Faraz]

Open in the dark, snip a small piece off and do a safelight test.

A 902 filter is Amber in colour, very expensive new, though they do pop up on Ebay now and again.

 

[Ian Grant]

A 902 filter is the same as a Kodak Wratten OC, or Photax/Paterson VC dome. The paper is fine with an orange/red safelight as well.

Ian

 

[Ian-Barber]

The paper works fine under red light, not much call for G1 though I guess

 

[Ian Grant]

In over 50 years of darkroom printing I think I've used Gd 1 once.

An Ilford 902 or 906 10x8 safelight filter is now £87.51. I have the formulae for making various Safe-Light filters . . . . . . . . . . .

Ian

 

[Ian-Barber]

In over 50 years of darkroom printing I think I've used Gd 1 once.

Seem a shame to throw it away, 70+m on that roll

 

[Reginald S.]

...not much call for G1 though I guess...

Ugh - I freezed some 108cm G1 paper rolls for mistreating as paper negatives - less harsh, and no timerobbing yellow filter needed






I have found decades old Ilfospeed G1 being exprisingly contrasty and always giving an excellent print if my other papers failed.
Must be some magic in the emulsion..

 

[Ian-Barber]

Ugh - I freezed some 108cm G1 paper rolls for mistreating as paper negatives - less harsh, and no timerobbing yellow filter needed

Now there is a good use for it, I will try that

 

[thronobulax]

There are also techniques you can try to fiddle the developer to increase contrast. For example, you can extend development time ore decrease dilution or both (but only to the point where you get paper fog).

There is also chemical magick to be tried. For example, this developer mixed 1:1 (or maybe even straight stock, who knows) is said to deliver up to 1 full grade more contrast for a given paper (Potassium Bromide being the "magick" in this case, I believe):

ID-14 High Contrast Press Developer

Metol 1.5 g
Sodium Sulphite (anh) 50 g
Hydroquinone 12 g
Sodium Carbonate (anh) 37.5 g
Potassium Bromide 2 g
Water to 1 litre

Finally, you can intentionally expose/develop some film to make higher contrast negatives that will print "normally" on G1 paper.

(But the idea of using it for paper negs is also really cool.)

 

[Ian Grant]

It's not the Bromide level in ID-14 causing the increased contrast, rather it's the overall balance of the developer. It's the higher pH and different MQ ratio, and its use at a more concentrated dilution.


ID-20 Ilford "Universal" Developer

Metol	3 g
Sodium Sulphite (anh)	50 g
Hydroquinone	12 g
Sodium Carbonate (anh)	60 g
Potassium Bromide	4 g
Water to	1 litre

To use: Photographic papers - Dilute 1+ 3 (can be 1+2 or 1+1 for higher contrast)

ID-62 is the modern PQ variant of this formula
ID-20 was once commercially available in powdered form, and in the 1950's/60's Ilford sold an ID-20 PQ powdered version.

Ian

 

[thronobulax]

It's not the Bromide level in ID-14 causing the increased contrast, rather it's the overall balance of the developer. It's the higher pH and different MQ ratio, and its use at a more concentrated dilution.
<Snip>
Ian

That's interesting. Can you say a bit more about this, perhaps? I'd be interested in the detail of some of the chemistry tradeoffs when creating such developers. (An external reference is more than adequate.)

 

[Ian Grant]

Compare the working strength solutions:

	ID-14	ID-20 1+3	ID-20 1+1
Metol	1.5g	0.75g	1.5g
Sodium Sulphite (anh)	75g	12.5g	25g
Hydroquinone	12g	3g	6g
Sodium Carbonate (anh)	37.5g	15g	30g
Potassium Bromide	2g	1g	2g
Water to	1 litre	1 litre	1 litre

ID-14 use: Full Strength for highest contrast. Can be used at 1+1 or1+3 for lower contrast.
ID-20 use: Photographic papers - Dilute 1+ 3 (can be 1+2 or 1+1 for higher contrast)

If you compare ID-14 to ID-20 first appearances are deceptive, ID-14 has half the Metol and Bromide and less Carbonate.

But ID-14 is used at Full Strength for Highest Contrast, you can use ID-20 at 1+1 for higher contrast, but if compared look at the critical differences, ID-14 has25% more Carbonate and double the Hydroquinone, triple the Sulphite, the MQ ratio is 1:8 in ID-14, 1:4 in ID-20 at 1+1. The Metol and Bromide levels are the same.

Increasing the Hydroquinone needs that increase in Carbonate as there's less super-additivity from the lower Metol ratio, and along with more Sulphite which enables cleaner working.

Ian

 

[thronobulax]

Compare the working strength solutions:

	ID-14	ID-20 1+3	ID-20 1+1
Metol	1.5g	0.75g	1.5g
Sodium Sulphite (anh)	75g	12.5g	25g
Hydroquinone	12g	3g	6g
Sodium Carbonate (anh)	37.5g	15g	30g
Potassium Bromide	2g	1g	2g
Water to	1 litre	1 litre	1 litre

ID-14 use: Full Strength for highest contrast. Can be used at 1+1 or1+3 for lower contrast.

ID-20 use: Photographic papers - Dilute 1+ 3 (can be 1+2 or 1+1 for higher contrast)

If you compare ID-14 to ID-20 first appearances are deceptive, ID-14 has half the Metol and Bromide and less Carbonate.

But ID-14 is used at Full Strength for Highest Contrast, you can use ID-20 at 1+1 for higher contrast, but if compared look at the critical differences, ID-14 has25% more Carbonate and double the Hydroquinone, triple the Sulphite, the MQ ratio is 1:8 in ID-14, 1:4 in ID-20 at 1+1. The Metol and Bromide levels are the same.

Increasing the Hydroquinone needs that increase in Carbonate as there's less super-additivity from the lower Metol ratio, and along with more Sulphite which enables cleaner working.

Ian

That's really instructive. Thanks for taking the time!