Metal Halide vs led

[Doug S]

After doing side by side exposures using the amerigraph 150 Brandt gave me and the Lawson led unit, I most definitely will use the metal halide for any halftone work and most definitely discharge screens.  The led I will use for most of the everyday stuff we do but there is no comparison when it comes to exposing and maintaining halftones with the metal halide. 

Using a 150 s mesh with no linearization I was able to keep all of the halftones down to 4% with 45 lpi.  With the led, I could achieve down to 8% but lost some at 80 and above. 

I'm modifying this because I know this is common knowledge but this is the first time I've been up close and had access to both types of exposure units in my shop to test.  I've heard this mentioned several times but seeing is believing.

[244]

After doing side by side exposures using the amerigraph 150 Brandt gave me and the Lawson led unit, I most definitely will use the metal halide for any halftone work and most definitely discharge screens.  The led I will use for most of the everyday stuff we do but there is no comparison when it comes to exposing and maintaining halftones with the metal halide. 

Using a 150 s mesh with no linearization I was able to keep all of the halftones down to 4% with 45 lpi.  With the led, I could achieve down to 8% but lost some at 80 and above. 

I'm modifying this because I know this is common knowledge but this is the first time I've been up close and had access to both types of exposure units in my shop to test.  I've heard this mentioned several times but seeing is believing.

Not all LED exposure units are the same. If you get a chance compare your exposure against a Starlight.

[Doug S]

Rich, I'm sure the starlight is better by far than the one I have.  That is one of the times I wish I had waited a little longer instead of biting at the first one.  The starlight hadn't came out yet when I bought it.  In fact, that is the only piece of equipment I have that doesn't have M&R stamped on it. 

[244]

Rich, I'm sure the starlight is better by far than the one I have.  That is one of the times I wish I had waited a little longer instead of biting at the first one.  The starlight hadn't came out yet when I bought it.  In fact, that is the only piece of equipment I have that doesn't have M&R stamped on it.

I understand. Just clarifying for others that all led will not perform the same. We have people holding way more dots than 8%.

[jvanick]

After we got our emulsion thicknesses under control, the starlight has been awesome.

4% to 95% linearized (printed) 50 lpi dots are no problem at all...

(actually even with the thicker coatings we were still ok with the halftones)

[kingscreen]

We won first place in the 2014 Impressions Awards for True Color Process Printing;  CMYK on a DC underbase. All screens were burned on our Starlight.

[ffokazak]

"In fact, that is the only piece of equipment I have that doesn't have M&R stamped on it"

That and the Amergraph

[alan802]

The Lawson sounds like it's as strong or stronger than the Vastex.  If you're holding those dots with your LED then that's better than what we can get consistently with the Vastex, but there are other variables at play so it's not exactly apples to apples unless we had them both here at our shop.  To hold anything under 10-12% over 50 lpi on the Vastex requires severe underexposure.  I know there seems to be at least one exception to the lackluster results of LED expo units so that's good news but overall, IN MY OPINION ONLY, LED has not come close to living up to the hype.  I know everyone is wanting LED to be the greatest thing since sliced bread and perhaps one day it will be for all the units out there.  I still get upset thinking about our unit and whether or not something as simple as putting an expo calculator on a screen and testing the unit actually happened.  We've got our stuff dialed in around here and the fact that we can't achieve decent halftones tells me that a few balls were dropped before the release of our exposure unit to the public. 

[islandtees]

The Lawson sounds like it's as strong or stronger than the Vastex.  If you're holding those dots with your LED then that's better than what we can get consistently with the Vastex, but there are other variables at play so it's not exactly apples to apples unless we had them both here at our shop.  To hold anything under 10-12% over 50 lpi on the Vastex requires severe underexposure.  I know there seems to be at least one exception to the lackluster results of LED expo units so that's good news but overall, IN MY OPINION ONLY, LED has not come close to living up to the hype.  I know everyone is wanting LED to be the greatest thing since sliced bread and perhaps one day it will be for all the units out there.  I still get upset thinking about our unit and whether or not something as simple as putting an expo calculator on a screen and testing the unit actually happened.  We've got our stuff dialed in around here and the fact that we can't achieve decent halftones tells me that a few balls were dropped before the release of our exposure unit to the public.

You need to get a Starlight, you're opinion on LED will change.

[alan802]

I understand the M&R is better, and I always try really hard to preface my comments by excluding from the negative remarks I'm about to make... but it doesn't usually work.  It has to be far superior to the Vastex but there are still Starlight users that have had a few of the exact same screen failures as I've had.  That doesn't mean it's still not by far the best LED unit it just means it's not a perfect expo unit.  If we're holding up a 7-10K metal halide unit as the highest (relatively speaking of course) quality light source for all of our needs then every LED unit BESIDES THE M&R isn't even close.  Where does the Starlight fall in that comparison to the big metal halides?  I haven't a clue really, but I don't believe it's on par with them.  Just my opinion which shouldn't upset anyone, it's just an opinion from someone who doesn't really matter in the grand scheme of things.

[Homer]

I think the LED really excels when paired with a DTS...I used it both ways and we could NOT be happier with our Starlight paired with the DTS. using a diazo emulsion as well.

[Inkworks]

I think you need to be a pretty big shop to have an exposure unit as a production bottleneck, if it is, then LED may just be the answer, although I'll put my old converted 3K Nuarc fliptop with an 8+ year old bulb in it up against just about anything for speed on just about any emulsion.

If you're looking at both MH and LED new, and the costs are similar, as well as the finished product, I see no reason to not go with LED, but so far we've heard and seen mixed reviews of LED, and with used MH readily available at great prices, it's a tough sell to many shops.

[Ross_S]

I'd say something is not calibrated on your units.  I also own a starlight and I-Image and I couldn't be happier.  I actually feel we hold more detail now with this set up versus film and MH. 

[blue moon]

And on the other end of the spectrum, we used the Vastex unit without problems and are now on a cheap SAATI unit that Alex was having problems with. It is closing on 6 months now without any issues. We are holding a calibrated 4% dot at 55 lpi. Results were very simar with the Vastex. Using the PHU2 we are running discharge without any issues.  With both units we only tested using the photo polymer emulsions. The other factor might be that our screens are bone dry (below 20% humidity) when developing.

Pierre

[jvanick]

Emulsion thickness plays a HUGE role in how your screens will behave with a LED unit.

If you're over 25% EOM you'll have a ton of issues, many that may be covered up with a MH unit...