Hygrometer suggestion?

[Zelko-4-EVA]

depends on the dehumidifier - 

http://www.grainger.com/Grainger/wwg/search.shtml?op=search&N=25517&in_dim_search=1

30, 50, 65, 104 pints per hour @ a certain RH will indicate how effective the dehumidifier will be at a certain temperature

[ScreenFoo]

What are the max temps I should keep the emulsion at?

That dehumidifier puts out a fair amount of heat.

I don't worry too much about coated screens since they turn over fast, but if the screen room is over 90 degrees or so I stick it in the fridge for the hot part of the day.  Not sure about photopolymers, but diazo doesn't like hot.
Probably wouldn't be a huge issue for us since a gallon rarely lasts a month in the summer, but if you're pushing your shelf life it may be more of a concern.

[mraph]

ok , on the hygrometer Radio shack should be aprx 19-20 dollars  cheap investment

get one it tells you what your humidity level is

a de humidifier will lower the humidity level the hygrometer tells you were you are at and what to keep it at

the sweet spot for emulsion is 32 % humidity  , under 40% and I am happy

Good luck

[Orion]

We keep our dark room at about 75 degrees and 40% humidity.  We bought a nice litte dehumidifier from Lowes a while back and it stuggles to keep it at 40%.  I think the humidity is more important than temp, and we've had our dark room at 68 degrees to 90 and everything in between without any noticeable difference in dry times.  But 60% humidy versus 45%, huge difference in dry times.

Definitely right Alan. Low humidity and air circulation are most important. If you are using a pure photo polymer emulsion it hates the heat.

[Gilligan]

"heat" is a very subjective term.

Give me some actual numbers.

[Orion]

From Kiwo:

5. DRYING
Dry emulsion coated screens in complete darkness, or under
safelight conditions, in a horizontal position with the substrate side
facing down. Temperature, relative humidity and airflow affect the
drying time. Screens must be dried thoroughly before exposing to
achieve highest chemical (ink and ink cleaners) and mechanical
(abrasion) resistance. Environmental conditions play a vital role.
Temperatures of 86°-104°F (30°-40°C) with a relative humidity of
30% - 50% maximum and moderate airflow are optimum conditions.
Drying at room temperature and in uncontrolled conditions may lead
to inconsistent results and varying screen resistance.
TIP: Keep screens and all screen handling areas dry until exposure
is complete. This includes storage, exposure preparation, and
exposure areas, as photo emulsions reabsorb moisture if
reintroduced to high humidity environments. Emulsions do not
become humidity resistant until exposure, washout and drying are
complete.

Looks like 104 is the high recommened for most emulsions. I keep my mine at 85 or less because my I-jet does not like 85 or higher in the darkroom. She is a beotch. The humidity level is the most important factor, I think?

[Gilligan]

Thank you for that info.

[Frog]

My dehumidifier brings my cabinet up to about 90-95

[mk162]

mine does about the same as frogs

[mraph]

heat can affect emulsions , especially pure photo polymer emulsions. as a supplier we keep emulsions stored in the basement of the warehouse during the summer months.

Humidity affects the proper drying of the stencil , even if it feels dry to the touch a humidity area can allow moisture to remain in the  stencil , this will affect proper exposure , resolution and durability.
 so an inexpensive hygrometer is a low investment for a long term solution
just my opinion