How to measure a p2p25 on a clear substrate?

[FKarlone]

I am printing a G7 test form CMYK on clear with a white flood over the CMYK, It is for a back lit process.
In the past I have simply read the target using the reflective function of the i1 and Profile Maker Measure Tool through the substrate.
This gives mixed results, I would like to use the transmissive function of the i1, but I cant figure it out.


So my question is how do I use the i1 to read a target printed on clear on a light box?

[meddington]

The i1 isn't actually designed for transmissive measurement (as was the SpectroscanT or the DTP-41T). Instruments by BarBieri are capable of transmissive measurement as well.

For the i1, I'd say your best bet is likely your original route with relective measurement and with an opaque white backing, then potentially boosting the curves of the profile to compensate for washing out by the backlight and the opacity of the white flood. Then there's the issue of the color temp of the backlight. interesting problem.

I would think this might be best addressed as an emissive measurement with the actual backlight, rather than transmissive without it, but that's not possible with the the i1 and current software other than monitor measurement...maybe with a spectroradiameter.

[rich apollo]

Interesting question. I think you're gonna' want to set up your i1 in emissive mode on a light box that uses the same light source that your final product would go in.

rich

[meddington]

The problem there is getting measurements. From the software's perspective, emmisive measurement invariably means that the software is displaying a series of patches on dynamic screen, rather than a transparent, static hardcopy print with a backlight. I'm thinking you'd have to measure with MeasureTool in emmisive mode, patch by patch manually and enter the Lab values into an excel sheet or something...sounds like a fun day in front of a lightbox in the Mall foodcourt. I do tend to complicate things though ...anyone see an easier solution?

[rich apollo]

> {quote:title=meddington wrote:}{quote}
> ...anyone see an easier solution?

Get an intern to do it. Promise them a pretzel and an Orange Julius if they finish by lunch time.

[FKarlone]

Thanks fellas,

I read them through the base using the reflective mode. The curves idealink makes are surprisingly normal compared to the other substrates we use for our screen printing process.

One at a time, Measure Tool, Excel, good idea, if the easy way does not work then I will try this.

We have a mockup of the standard "Drive Through" light box. I could see me in a "Taco Bell" drive through however!

We will have to adjust the curves on the fly, which is what we did before.

I just wanted a mechanical approach instead of color by committee!


Thanks again,

Karl Jennex
Graphic Tends
Paramount, CA

karl@graphictrends.net