Questions about gum printing

[Pete Watkins]

I'm on the verge of creating my first gum print in the next few weeks. I've read the books and scanned the net but a few points are still not clear.
Is hardening the paper after the initial sizing necessary?
I intend to use Chrome Alum as my hardener and the method that I intend to use is a 0.5% solution. Placing the paper in this for 2 minutes then washing it in running water. Does this sound O.K.?
Do you resize after every pass?
Do you re-harden after every pass?
I intend to use Sodium Benzoate to preserve my gum solution. I've got two different solutions suggested. One is mixing 1g of Benzoate in 10ml of water and adding 5ml to 1 litre of gum solution. The other is using a 0.25% solution of Benzoate but the author fails to suggest how much to add to 1 litre of gum solution. Any suggestions, please?
I intend trying Ammonium Dichromate first and have read that the Dichromate solution will last a few months. Is this about right?
Some authors suggest that the first pass should be carried out using a gum/dichromate solution with no negative and no pigment, has anybody got an opinion on this?
Does anybody wet coat the paper?
Sorry to ramble on but there seem to be so many differing opinions out there.
Thanks for any help offered.
Pete.

[Brian Ellis]

I used to do a lot of gum printing but it was so long ago that I've forgotten almost everything I knew which wasn't a whole lot to start with. There are lots of ways to do it and as you have seen, lots of different opinions on how to do it. I'd suggest buying one of several books available on gum printing and just do what the author says to do for starters. One new book that includes a chapter on gum printing is here. http://www.alternativephotography.com/wp/alt-proc/gum-printing-and-other-amazing-contact-printing-processes. I used to know the author fairly well and I'd be comfortable doing anything she says to do. Also she is, or at least used to be, very accessible by phone or email so I think she'd be happy to answer any questions you had after reading the chapter on gum printing.

[Pete Watkins]

Thanks Brian,
I've ploughed through a lot of books. The Gum Bichromate Book, The Silverprint Handbook, Beyond Monochrome, Coming into Focus, Historic Photographic Processes and The Book of Alternative Photographic Processes by Christopher James. A couple of others as well. Everybody seems to have a different opinion and method of doing things. These are not like the "subtle" differences in normal mono printing, they seem to be massive. Thanks for your advice though.
Pete.

[BarryS]

Pete-- My advice is to keep things simple starting out. For single color gum prints, I don't harden or size the paper. I use Fabriano Artisico Extra White and it has internal and surface sizing. For multiple colors, you would pre-shrink and size just once before you print. I use sodium benzoate at 1 g/l--the concentration is not critical. I use potassium dichromate and the solution seems long lasting--at least six months. A no-pigment first pass sounds like a waste of time--never heard of anyone doing that. Just coat the dry paper with your dichromated pigment gum solution with a brush--what is "wet coating"?

Stop reading and start experimenting--it's a very simple process. :)

[Pete Watkins]

Many thanks Barry. That really helps. I have both Ammonium and Potassium Dichromate but plan to start with Ammonium. I'll try to find the paper that you've recommended.
Thanks again,
Pete.

[Jim Noel]

I used to do a lot of gum printing but it was so long ago that I've forgotten almost everything I knew which wasn't a whole lot to start with. There are lots of ways to do it and as you have seen, lots of different opinions on how to do it. I'd suggest buying one of several books available on gum printing and just do what the author says to do for starters. One new book that includes a chapter on gum printing is here. http://www.alternativephotography.com/wp/alt-proc/gum-printing-and-other-amazing-contact-printing-processes. I used to know the author fairly well and I'd be comfortable doing anything she says to do. Also she is, or at least used to be, very accessible by phone or email so I think she'd be happy to answer any questions you had after reading the chapter on gum printing.

I have at least a dozen books which contain a chapter, or are exclusively devoted to Gum printing. Christina's book is by far the most up to date, and the most accurate. It is th eonly one I now recommend to students. I realize you have several others, but by al means acquire this one.

[Tom Sobota]

Pete,
There are indeed many variations of the technique.
As you have been told, there are papers that you can use without sizing. But once you size with gelatine, by all means harden the gelatine coat(s)!
I harden with formaldehyde, but chrome alum is less obnoxious. Be ready to wait a few days before the size is well hardened. I never heard that you have to wash the paper afterwards. Seems a bit self-defeating since chrome alum is slow.
I resize and harden only once.
The dichromate solutions are usually used to saturation, and there is usually an undisolved and harmless deposit in the bottom. Now Pot. Dichr. reaches saturation at around 18% while Amm. Dichr. saturates at 33% or so. Keep that in mind.
The dichromate solutions last several years, in my experience. There is no "best before". In normal use you will be taking small quantities with a graduated pipette, so there's very little risk of contaminating the solution. Hence, it lasts ...
I have read about a first coat with unpigmented gum. Well, it is a hardener, go ahead and try...
In principle you can coat wet paper, but there's a danger of abrading the surface, since wet paper is much softer. Also, the pigment will probably get more into the paper. I don't really know, I have never tried this.
Don't forget the clearing disulphite solution ath after you have finished printing, unless you really like the yellowish hue :-)

Tom

[Pete Watkins]

Thanks Tom,
That's very helpful. I'm feeling more confident all the time. I've written out about 14 pages of different options and methods and the posters here are helping me to form a personal method for my own gum prints.
Many thanks,
Pete.