light source (distance) for two screens at a time? 23x31's

[Frog]

It will become obvious to new users, but with a set of common screen sizes used, shops with these wall units end up with a series of marks on the floor to which the different light-to-screen distances apply. (of course, a chart relating this one new variable to use along with mesh and emulsion time or light unit figures will be another obvious addition)

And yes, I first used these marks with a carbon arc. Flat stock shops I worked typically exposed screens anywhere from "36x48" to 48"x72"

[mimosatexas]

Did you pick up that ridiculously big but cheap one on Craigslist a month or so ago?  It was at a sign maker's shop downtown and he was moving and didn't want to take it with him.  I was on my way down to pick it up when our pressure washer and our AC for the sales offices went down at the same time and obviously didn't make it down to pick up.

yep!  $250 and it works flawlessly.  The pump alone is worth a lot more than that...

I actually tried to buy it from him about a year ago but he changed his mind about selling it at that time.  I was psyched when I saw it come up again.

[alan802]

I had no clue what I was going to do with it but at that price you could flip it and make $1000 if you had a few months to find a taker.  I was thinking about loading up 4 screens in it and rolling it out in the parking lot and shoot 4 at a time while we were burning 2 with the Richmond.  It could have tripled our screen output and served as a backup if/when the Richmond keypad craps out, which could be any second now since the membrane buttons are very worn and not working properly. 

[screenprintguy]

I was just going to say, call Ron Hopkins that dude is the GURU of exposure systems, but it looks like he already found the thread!!

[mimosatexas]

I badly needed it for my large screens for posters and all over prints etc.  I was kind of doing them in the most low tech way possible and the results sucked, and was trying to build a unit but kept not having any free time.  I don't know if it will replace my regular unit for standard screens, but it sure is nice for my big stuff.

And like you said, no risk to buying it.  If I find I don't really need it down the road it is in fantastic condition and they sell for 5x that or more on digitsmith with some frequency.

Now I just need a 3k, 5k, or better light source...

[Frog]

I badly needed it for my large screens for posters and all over prints etc.  I was kind of doing them in the most low tech way possible and the results sucked, and was trying to build a unit but kept not having any free time.  I don't know if it will replace my regular unit for standard screens, but it sure is nice for my big stuff.

And like you said, no risk to buying it.  If I find I don't really need it down the road it is in fantastic condition and they sell for 5x that or more on digitsmith with some frequency.

Now I just need a 3k, 5k, or better light source...

I have a 5K Olec and Integrator, but I'm not much into crating and shipping.

[Sbrem]

I need that old "rule of thumb" info where you x your screen frame size by X to get your light source (distance) for two screens at a time? 23x31's  This is for a wall mount exp.  I think I recall 40" but that can change based on the screen frame size. Here, we are doing two 23x31's placed horizontal or side by side.

Anyone remember what that is?

Dan, you have an in with your comrades at NuArc, bet they could answer precisely...

The 1.5 times the diagonal rule came from the days of Carbon Arc light sources, and yes I was with NuArc when we manufactured Carbon Arc Units.  The reflector on carbon arc units was as much of an air deflector as it was a light reflector, so as not to affect the light output from the burning carbons.  Over the years reflector designs changed to get better coverage at different distances.  As an example our Trilight unit that has been on the market for around 15 years and will handle up to a maximum of a 42"x60" screen.  The glass to lamp distance on the Trilight is 31". 

As was already mentioned, increasing the lamp to glass distance will greatly increase the exposure time, which was one of the main reasons for the reflectors that we use today.  There is nothing wrong with the 1.5 rule, and if you do increase the distance you will get a little better coverage, but the down side is that it will take longer to expose the screen.

Ron Hopkins
NuArc Sales Mgr.
M&R Sales and Service Co.

I learned on a NuArc carbon arc lamp, great light source, lots of poison, but a great light source...

Steve

[Dottonedan]

It will become obvious to new users, but with a set of common screen sizes used, shops with these wall units end up with a series of marks on the floor to which the different light-to-screen distances apply. (of course, a chart relating this one new variable to use along with mesh and emulsion time or light unit figures will be another obvious addition)

And yes, I first used these marks with a carbon arc. Flat stock shops I worked typically exposed screens anywhere from "36x48" to 48"x72"

LOL.  Yep,  Thats what we did. Marked the foor.  LOL.

[Dottonedan]

I need that old "rule of thumb" info where you x your screen frame size by X to get your light source (distance) for two screens at a time? 23x31's  This is for a wall mount exp.  I think I recall 40" but that can change based on the screen frame size. Here, we are doing two 23x31's placed horizontal or side by side.

Anyone remember what that is?

Dan, you have an in with your comrades at NuArc, bet they could answer precisely...

The 1.5 times the diagonal rule came from the days of Carbon Arc light sources, and yes I was with NuArc when we manufactured Carbon Arc Units.  The reflector on carbon arc units was as much of an air deflector as it was a light reflector, so as not to affect the light output from the burning carbons.  Over the years reflector designs changed to get better coverage at different distances.  As an example our Trilight unit that has been on the market for around 15 years and will handle up to a maximum of a 42"x60" screen.  The glass to lamp distance on the Trilight is 31". 

As was already mentioned, increasing the lamp to glass distance will greatly increase the exposure time, which was one of the main reasons for the reflectors that we use today.  There is nothing wrong with the 1.5 rule, and if you do increase the distance you will get a little better coverage, but the down side is that it will take longer to expose the screen.

Ron Hopkins
NuArc Sales Mgr.
M&R Sales and Service Co.

Thanks Ron, for chiming in.  Very nice. We were able to narrow down a pretty decent 65lpi holding the 5% dots but given that their standard will be 55lpi, we were spot on at the 305 mesh.

[RonH]

I need that old "rule of thumb" info where you x your screen frame size by X to get your light source (distance) for two screens at a time? 23x31's  This is for a wall mount exp.  I think I recall 40" but that can change based on the screen frame size. Here, we are doing two 23x31's placed horizontal or side by side.

Anyone remember what that is?

Dan, you have an in with your comrades at NuArc, bet they could answer precisely...

The 1.5 times the diagonal rule came from the days of Carbon Arc light sources, and yes I was with NuArc when we manufactured Carbon Arc Units.  The reflector on carbon arc units was as much of an air deflector as it was a light reflector, so as not to affect the light output from the burning carbons.  Over the years reflector designs changed to get better coverage at different distances.  As an example our Trilight unit that has been on the market for around 15 years and will handle up to a maximum of a 42"x60" screen.  The glass to lamp distance on the Trilight is 31". 

As was already mentioned, increasing the lamp to glass distance will greatly increase the exposure time, which was one of the main reasons for the reflectors that we use today.  There is nothing wrong with the 1.5 rule, and if you do increase the distance you will get a little better coverage, but the down side is that it will take longer to expose the screen.

Ron Hopkins
NuArc Sales Mgr.
M&R Sales and Service Co.

Thanks Ron, for chiming in.  Very nice. We were able to narrow down a pretty decent 65lpi holding the 5% dots but given that their standard will be 55lpi, we were spot on at the 305 mesh.

Sometimes it takes a village!