Eye one uv or non uv version for profiles

[dub]

I am looking at upgrading my DTP-45 to an eye one and the i1i0 table and was wondering if I could get away with the non-uv eye one for profiling of proofers and press sheets.

Currently we are running EFI colorproof XF and I under measuring devices I don't see it asking for eye one uv, it just list eye one so I don't think their would be an issue there.

Alternatively I guess I could just buy one of each and use the UV for proofs and the non-uv for press sheets but it would be nice to have just one device.

Thanks in advance for the info...

-Dub

 

[meddington]

Do you have a compelling reason for using a uv-cut filter for proofing and no filtration for press?

Do you plan to use the device to verify proofs to a standard data set?

My default opinion is to forgo the uv-cut filter as it can cause as many or more problems as it claims to solve, but its sometimes nice to have both.

 

[Werby]

Hi Mike

What kinds of problems have you seen from a UV-cut filter?

Both CGS (ORIS) and GMG recommend UVcut when doing iterative color matching on those RIPS, so I use a UVcut eye1 when verifying those proofs. Of course if you use one of their stock that doesn't have any optical brighteners, it doesn't really matter, but for stocks with brighteners I have found that the color match (with UV included) is definitely too yellow in the highlights/paper white. I guess I just don't like the way my Isis "sees" optical brighteners.

 

[dub]

Thanks for the Reply Mike: you are correct in that in the near future we are going to be reading proofs and verifying to a standard data set but as Werby points out, getting a proofing stock with no optical brighteners added would be an idea as well.

Werby: not sure if you have found this out yet, but Xrite does have an optical brightener compensation (OBC) kit available for the ISIS for use with Profile maker or Monaco. It's a software patch or plugin for use with the ISIS only currently. I am not sure if you need to have a UV cut ISIS or if it works with the normal as well but with the compensation being done at the software level and hopefully some adjustability would be ideal.

thanks agin,

Dub

 

[meddington]

What kinds of problems have you seen from a UV-cut filter?

Both CGS (ORIS) and GMG recommend UVcut when doing iterative color matching on those RIPS, so I use a UVcut eye1 when verifying those proofs. Of course if you use one of their stock that doesn't have any optical brighteners, it doesn't really matter, but for stocks with brighteners I have found that the color match (with UV included) is definitely too yellow in the highlights/paper white. I guess I just don't like the way my Isis "sees" optical brighteners.

The main problem I have with UV excluded instruments is that they don't take into account the ambient lighting conditions, which play a large roll in how optical brighteners affect the visual appearance. The color cast you may see with UV included measurements could actually go either way. If lighting conditions contain more UV than the spectrophotometer illuminant, the increased fluorescence can give the print a blue cast . If lighting conditions contain less UV than the spectrophotometer illuminant, then the reduced fluorescence will give the print a yellow cast in that particular lighting. A UV-cut in this case pretends there is no UV component in the ambient light at all, and the results may or may not be appropriate.

Another issue is when comparing measurements with published data (proof verification for example). Current SWOP, Gracol (TR001, TR003, TR005, & TR006) and Fogra data sets are all UV included (no filtration utilized), and comparing measurement data from an instrument excluding UV can give ambiguous results. You iterated delta E may measure and report very low, but because of filtration differences, this may be artificial. Inter-instrument agreement in general plays a role here, but IMO filtration should remain consistent if the goal is to match UV included data. Ask the GMG guys if they used UV-cut filtration for submissions in the IPA Proofing Round-up.

There isn't a clear cut way to deal with optical brighteners that can be applied for all users. My two new favorite approaches to dealing with OB issues are the Xrite OBC module available with the Isis (or the Argyl CMS's approach) and the Just Normlicht LED based light box which allows for true removal of UV from the ambient light (among other cool features, such as matching the chromaticity of your monitor). Xrite's OBC takes the visual result under a particular light source into consideration, and although is relies on a UV excluded measurement, it also needs the UV included measurement as well.

 

[meddington]

Thanks for the Reply Mike: you are correct in that in the near future we are going to be reading proofs and verifying to a standard data set but as Werby points out, getting a proofing stock with no optical brighteners added would be an idea as well.

You might find it better to obtain a proofing stock that has similar OB content as the press stock. This sometimes isn't easy, but its equally tricky (or perhaps more so) to obtain both proof and press stock that contain no brightners...most press stocks have them now days.

The Isis contains both "full" spectral and UV excluded LEDs, so it can offer both UVi and UVx data, which is what makes the OBC kit effective.

 

[Werby]

My two new favorite approaches to dealing with OB issues are the Xrite OBC module available with the Isis... Xrite's OBC takes the visual result under a particular light source into consideration, and although is relies on a UV excluded measurement, it also needs the UV included measurement as well.

Since you brought it up, can you tell me more about the X-Rite OBC module? I have an older ISIS which didn't ship with the OBC module and X-rite wants $300 for it but they haven't been able to provide me with a shred of documentation on how it works. So you think it is worth $300? I've been wanting to get it but because X-Rite totally stonewalls me when I try to find out anything about it I figured it must be garbage. Marketing geniuses over there!

 

[meddington]

Since you brought it up, can you tell me more about the X-Rite OBC module? I

Basically it works like this...you print a test chart and measure it with the Isis in dual mode (both UVi and UVx), then print a grey patch test chart based on the measurements. Your print is then visually compared with a reference chart and you mark the closest patches. The software then compensates the measurement file, and you can then generate a profile. You'd probably find this most useful for clients using non-standard lighting, or in cases where two different light booths excite the OBs quite differently. I've never used this module, but the samples I've seen were quite dramatic...two prints that looked markedly different under the same lighting, but practically identical under the lighting for which they were optimized.

The Argyl CMS can do something similar (and its free... if you don't mind learning to control it via command line). Basically you take your spectral measurement data and create several different iterations based on D50 lighting with varying amounts of UV...from none (UVx) to nuclear, then output some images and make a visual assesment to determine the ideal amount of illuminant uv to include in the measurement data and base your profiles off that. Pretty much the same principle. Argyl also has the ability to mathematically compensate for flourecence in a more intelligent way...taking into account the level of UV in the instrument illuminant, the level of UV in the lighting illuminant, the level of OBs in the source media (press) and the level of OBs in the proofing media. To customize for a particular light booth, you'd need accurate spectral data of the lighting UV content, which you can't get from an i1 spectrophotometer...you'd need a spectroradiometer. This is probably going way overboard for a lot of scenarios though.