Re: Gum problem(s)

Well, all I know is that all I've ever used for gum printing is a
photoflood; it works great and gives a good sharp print, and while
there's some heat at the base of the bulb where it's screwed in (I
always make sure I've got a good heavy duty porcelain fixture to screw
it into) there is simply no heat 13 inches away where the print is.
Even after the longest exposure I've ever made, the glass and the print
itself is always still at room temperature.

I started with a photoflood because it was simple and cheap, and I
wanted to know for sure I wanted to do gum before I invested any money
into it. But the photoflood, and the rest of my makeshift setup,
worked so great for me that I've never felt the need to do anything
else.
kt

On Nov 18, 2005, at 11:37 AM, Kate M wrote:

> But isn't photoflood a tungsten light source? There would be very
> little uv
> output then, a lot of heat though.....when ever I've done copywork
> under
> photofloods, I've used tungsten film.
> Kate
>
> -----Original Message-----
> From: Katharine Thayer [mailto:kthayer@pacifier.com]
> Sent: Saturday, 19 November 2005 4:31 a.m.
> To: alt-photo-process-l@sask.usask.ca
> Subject: Re: Gum problem(s)
>
>
>
> Yves,
> Thanks for description.
>
> Okay,, this sounds like (1) pigment stain (not clearing in masked
> areas) and ... (2) ... hmmm, I'd need to see the print, I think. Your
> description of not much pigment in exposed areas sounds like
> underexposure, but 20 minutes under a photoflood is a very long
> exposure. My exposures are from 1 to 5 minutes with the same kind of
> light; most exposures are 2 or 3 minutes. But if you live in a very dry
> climate, you may need a longer exposure, as there is almost a vertical
> inverse relation between humidity and time required for hardening.
>
> Katharine
>
>
> On Nov 17, 2005, at 6:30 PM, Yves Gauvreau wrote:
>
>> Hi all,
>>
>> I tried a few variants in the pigment / gum ratio and coated to
>> different
>> tickness directly on paper using various exposition times. None of the
>> combination I've tried cleared to the paper in masked areas. Also I
>> tried
>> this with one dark brown watercolor paint tube and one using a dry
>> pigment
>> (dark brown also). I use a 1:1 ratio of pigment/gum and saturated pot.
>> dichromate solution.
>>
>> I also notice the unmask area don't hold much if any pigment either.
>> It's
>> like some pigments get into the paper causing a noticable darkening
>> and
>> almost none stays on top of the paper in insoluble gum. My last
>> attempt was
>> 20 minutes exposure under a #2 photoflood light.
>>
>> Any suggestion on what is the problem(s) and what I should try next?
>>
>> Thanks
>> Yves
>>
>> PS Both pigments I used seem to be of the opaque type if this could
>> help.
>>
>
>
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Received on Fri Nov 18 14:44:00 2005