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Author Topic: Lumejet Process Overview  (Read 7656 times)

amolitor

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Lumejet Process Overview
« on: February 22, 2018, 10:26:57 AM »

I confess that I did not perform a  DEEP read of this article, but it did not strike me as a particularly new thing at all?

People have been shining colored lights onto silver halide paper to make digital prints for a long time. I don't quite get how Lumejet is any
different from, say, a Durst Theta printer, which has been around for quite a while.

What am I missing?
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Mark D Segal

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Re: Lumejet Process Overview
« Reply #1 on: February 22, 2018, 10:49:40 AM »

....................

What am I missing?

The first half of the essay which describes their re-engineering of a long-standing process into one for which they claim superior outcome characteristics, and both Kevin and I determined does indeed produce very convincing prints.
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Mark D Segal (formerly MarkDS)
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Kevin Raber

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Re: Lumejet Process Overview
« Reply #2 on: February 22, 2018, 11:04:49 AM »

I have a more detailed video and information coming in an article I am working on in the next couple of weeks. 
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Kevin Raber
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amolitor

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Re: Lumejet Process Overview
« Reply #3 on: February 22, 2018, 11:37:32 AM »

With all due respect,  Mark, if there's anything in the essay that acknowledges that previous versions of this kind of process exist, it is quite small. The first half reads exactly as if the Lumejet guys worked away in their lonely engineering garret for 15 years, and then came out with this, the first and only example of this amazing new technology.

The word "Durst" does not appear in the article, according to my search box (I *did* take a few pro forma steps to check for obvious things I might have missed).

Your comparison is with an inkjet printer, not with, say, a Durst printer, or with DSI.

Overall, the impression one gets is that this is a sui generis process, with no antecedents. This probably is not what you intended, and perhaps the antecedents are so strong and obvious to you that you cannot imagine how anyone could read it differently. And perhaps the LuLa readers are sophisticated enough that this is true.
« Last Edit: February 22, 2018, 12:49:37 PM by amolitor »
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Wayne Fox

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Re: Lumejet Process Overview
« Reply #4 on: February 24, 2018, 08:35:01 PM »

and both Kevin and I determined does indeed produce very convincing prints.
As does a Lightjet, Durst Lamda and even a Chromira. but it's still just a C print exposed with LED light with all the longevity and gamut challenges of that process.

so when you say convincing, are you saying they look good (as do well made prints form those other devices) , or are you saying wow, this is really cool and new and is visually obviously superior to those.
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Mark D Segal

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Re: Lumejet Process Overview
« Reply #5 on: February 24, 2018, 09:16:00 PM »

Hi Wayne,

For avoidance of doubt, my review by intent and design does not focus on any other chromogenic process. My discussion has two basic components: (1) a description of their process based on what they say it does just so people know what it's about, and (2) a comparison of their prints with the prints that come out of my Epson SC-P5000; why - because I was interested in seeing, and thought readers would be likewise - how the output from this process compares with output from one of the finest inkjet printers on the market - i.e. comparing two very different and capable technologies. I also think  such a comparison could be of interest to all those who want prints but don't want to print, so would send their files out for processing say to a good quality C-print lab, or have their photos made into C-print books which these folks also do a lovely job of.

So when I say their prints are "convincing", what I mean is that if you look at them in isolation they really do like fine, and if you look at them compared with output from a first-rate inkjet printer, they still look fine. This is not only my opinion by the way - when I produce these comparisons I invite other pairs of experienced eyes to look-see before I submit for publication. Now of course, a sample of prints isn't a whole universe of prints, but a purpose-driven sample can tell a lot.

Comparing their chromogenic process with other chromogenic processes is also a valid exercise, but a whole other talk-show and fresh piece of quite time-consuming research - which I would welcome others to undertake if they're interested. :-) 

I agree with you that the gamut looks relatively challenging in theory when you examine their profiles, as I showed in the article, but in practice it turned out to be less of a big deal than I expected; but because of the gamut difference, different editing under softproof with bespoke profiles is needed between say a Lumejet output and an Epson SC-P5000 output on luster paper; this is pretty standard when trying to produce approximately similar image appearance from technologies or materials that have very different gamut or contrast ratios. Now maybe a different set of prints would tell a different story, but between Kevin and I, we did have them print quite a few different kinds of photos, as well as some standard evaluation targets, and they all looked very good. Longevity isn't my wheelhouse, but I think the general consensus is that they won't endure as well as pigment inkjet.
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Mark D Segal (formerly MarkDS)
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Wayne Fox

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Re: Lumejet Process Overview
« Reply #6 on: February 24, 2018, 10:18:05 PM »

Thanks for the perspective.

I guess as one who has owned and operated LED based silver halide printers for over 20 years (my first one was the Kodak "Pegasus" LED printer which produced pretty remarkable results), I just don't see this as a new process. I think those that have never seen many digital C prints are surprised that the "limited" gamut and "meager" 300 dpi resolution can result in very sharp prints with great saturation, smooth gradations,  and visually very competitive with high end inkjet prints.

So my curiosity is piqued ... have they really managed to improve the digital c print over previous technologies. Are they going to manufacture and sell the device to other labs? (seems that's would be their main goal, to market the technology). If you and Kevin can figure out how to test that it would be very enlightening.

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digitaldog

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Re: Lumejet Process Overview
« Reply #7 on: February 24, 2018, 10:25:51 PM »

FWIW Wayne, I agree with you 100%; nothing new about this print process, color gamut, archival qualifies and paper options not impressive in this century.
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Andrew Rodney
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Mark D Segal

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Re: Lumejet Process Overview
« Reply #8 on: February 24, 2018, 11:33:38 PM »

Thanks for the perspective.

I guess as one who has owned and operated LED based silver halide printers for over 20 years (my first one was the Kodak "Pegasus" LED printer which produced pretty remarkable results), I just don't see this as a new process. I think those that have never seen many digital C prints are surprised that the "limited" gamut and "meager" 300 dpi resolution can result in very sharp prints with great saturation, smooth gradations,  and visually very competitive with high end inkjet prints.

So my curiosity is piqued ... have they really managed to improve the digital c print over previous technologies. Are they going to manufacture and sell the device to other labs? (seems that's would be their main goal, to market the technology). If you and Kevin can figure out how to test that it would be very enlightening.

Wayne, for the core technology they're using existing machinery and materials - their claim is that they have substantially improved upon the existing technology in the ways described in the article - higher resolution, sharper output, improved colour accuracy relative to the file values. Now, how much better it is relative to other C-print producers I agree is an interesting question that deserves an independent evaluation, but to answer it one would need to research which lab(s) to test them against and possibly set-up a dialog with them; it's a big job. I'll discuss with Kevin and see what he thinks. I'm wondering how large the pool of interest in the LuLa community.

Oh - and I should add - I don't know that they have in mind to market their proprietary technology. I think they are aiming at expanding the print and book offerings from their own facilities.
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Mark D Segal (formerly MarkDS)
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digitaldog

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Re: Lumejet Process Overview
« Reply #9 on: February 25, 2018, 10:16:05 AM »

Let's not forget process control (consistency in output over time). I'm sure Wayne can tell us how much work it takes from the printers owner's end. But the end user expects (or should expect) the RGB values he output's today and in a year will look identical. And that's easy with modern ink jet printers. What's the dE drift when sending out colors today and in a month? Or among a lab using more than one machine. Again, with a modern ink jet (certainly Epson's and I've got plenty of colorimetric trending data), the differences are not visible.

Quote
The accuracy data metric is dE(00), comparing the file values of a 31 patch check wedge with the read values from the print of that check wedge (in Absolute Rendering Intent), provided along with the client’s print.
That sounds like marketing speak! If you send the IDENTICAL set of patches (and 31 is rather tiny) through a Spectrophotometer, you'll NEVER get a dE of 0.00! Impossible. There's noise in the individual readings of the same two sets of patches. Had the Marketing department who made this claim understood such a fact, they would have stated something like 0.04 or something like that (be happy to upload an actual colorimetric report of dE differences measuring the SAME target twice in a row).
« Last Edit: February 25, 2018, 10:26:05 AM by digitaldog »
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Andrew Rodney
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Kenneth Sky

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Re: Lumejet Process Overview
« Reply #10 on: February 25, 2018, 06:12:40 PM »

Mark,
What interests me more than the C-prints is their "photobook printing". At present, they ask clients to use In Design instead of providing a template of their own and only create the book block which needs to then be sent to a binder. The description sounds like it may be an improvement over the quality produced by most online photobook producers. From my discussion with them by e-mail, I've learned that Kevin may be using this service. It would be helpful to a lot of us if an evaluation of this product could be made. Even if it is subjective as opposed to time-intense objective testing.
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Mark D Segal

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Re: Lumejet Process Overview
« Reply #11 on: February 25, 2018, 07:06:31 PM »

Mark,
What interests me more than the C-prints is their "photobook printing". At present, they ask clients to use In Design instead of providing a template of their own and only create the book block which needs to then be sent to a binder. The description sounds like it may be an improvement over the quality produced by most online photobook producers. From my discussion with them by e-mail, I've learned that Kevin may be using this service. It would be helpful to a lot of us if an evaluation of this product could be made. Even if it is subjective as opposed to time-intense objective testing.

Kevin did have a book made and I'm sure he'll be talking about it in his forthcoming essay on Lumejet, and most likely that discussion would be subjective. If they really confine their ability to handle customer layouts to InDesign I think they will be limiting the scope of their market, as there are most probably many more people who would like to get books made than who use InDesign.
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Mark D Segal (formerly MarkDS)
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Mark D Segal

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Re: Lumejet Process Overview
« Reply #12 on: February 25, 2018, 07:14:41 PM »

Let's not forget process control (consistency in output over time). I'm sure Wayne can tell us how much work it takes from the printers owner's end. But the end user expects (or should expect) the RGB values he output's today and in a year will look identical. And that's easy with modern ink jet printers. What's the dE drift when sending out colors today and in a month? Or among a lab using more than one machine. Again, with a modern ink jet (certainly Epson's and I've got plenty of colorimetric trending data), the differences are not visible.
That sounds like marketing speak! If you send the IDENTICAL set of patches (and 31 is rather tiny) through a Spectrophotometer, you'll NEVER get a dE of 0.00! Impossible. There's noise in the individual readings of the same two sets of patches. Had the Marketing department who made this claim understood such a fact, they would have stated something like 0.04 or something like that (be happy to upload an actual colorimetric report of dE differences measuring the SAME target twice in a row).

Ya, they know a thing or two about process control. As mentioned in the article and on their website, they calibrate their machines every shift and provide step wedges with every job. So there is a high probability that what you print WITH THEM next year will come back looking the same as what you printed WITH THEM this year - but this doesn't mean that sending the same files to another kind of C-print lab will produce identical output. So on a closed loop basis it's probably reliable from job to job for the same file, but outside of that, not so sure.

dE(00) is an industry abbreviation for dE 2000. It has nothing to do with specific measurements - that's the dE formula they are using.
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Mark D Segal (formerly MarkDS)
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DougDolde

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Re: Lumejet Process Overview
« Reply #13 on: February 25, 2018, 07:30:18 PM »

Yes not a very impressive review (also a tough read) gotta wonder why it even got reviewed...to warn people off?
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elliot_n

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Re: Lumejet Process Overview
« Reply #14 on: February 25, 2018, 08:11:55 PM »

It's always interesting to hear of new print services. I'll probably give them a spin, although I too am puzzled as to whether they are offering anything radically different from Lightjet or Lambda printing (which are well-catered for here in London). They operate from an industrial estate in Coventry, so I guess it's mail-order only. And their maximum print width seems to be 30cm (up to 100cm long) – so no exhibition prints, just books and (small) portfolios. To their credit, they've garnered some good testimonials. It's rather confusing that they have two websites:

http://www.l-type.com/
https://www.lumejet.com/
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digitaldog

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Re: Lumejet Process Overview
« Reply #15 on: February 25, 2018, 09:39:51 PM »

Ya, they know a thing or two about process control. As mentioned in the article and on their website, they calibrate their machines every shift and provide step wedges with every job.
That may be what they say, have you measured and reported output trending? Over what time frame and what average (and as importantly max) dE?
Quote
So there is a high probability that what you print WITH THEM next year will come back looking the same as what you printed WITH THEM this year
Any outside data to support that?
Quote
dE(00) is an industry abbreviation for dE 2000. It has nothing to do with specific measurements - that's the dE formula they are using.
It is, an industry abbreviation for dE 2000, where? Not seeing it here or here or here etc.
Quote
So on a closed loop basis it's probably reliable from job to job for the same file, but outside of that, not so sure.
Probably, perhaps but we really don't know do we? Be kind of interesting to have them output actual targets of a lot more color patches over time and measure them independently.
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Andrew Rodney
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Re: Lumejet Process Overview
« Reply #16 on: February 26, 2018, 07:03:08 AM »

The major thing that seems to be missing from the article and their web-site is the cost. So it wasn't clear to me whether I was supposed to think that this means I should no longer have an Inkjet at home, or if it was a low-cost better quality alternative to Blurb, or...
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elliot_n

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Re: Lumejet Process Overview
« Reply #17 on: February 26, 2018, 07:31:15 AM »

There are links to PDF price-lists at the bottom of this page:

http://www.l-type.com/order

An 8x10 inch print costs £9.48 (inc VAT).

Theprintspace (a popular London lab, using Lambdas - I think) charge £6.86 for the same.

But L.Type's thing seems to be mounting prints, either to thin board, or back to back. Theprintspace will do the former, but then the price goes up to £14.11 (whereas L-type remains £9.48). Theprintspace doesn't do the latter. It is this feature (back-to-back printing) which makes their service interesting (for c-type portfolios).

« Last Edit: February 26, 2018, 07:39:56 AM by elliot_n »
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Kevin Raber

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Re: Lumejet Process Overview
« Reply #18 on: February 26, 2018, 09:12:33 AM »

I will have a video and article on this printing process in the next week or so.  Pricing, ordering and a more in-depth look at the products will be part of this.  This is an interesting service for those that don't want to do printing or are looking for portfolios or books.  I am traveling this week and this article is top on my list for next week.
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Kevin Raber
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Mark D Segal

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Re: Lumejet Process Overview
« Reply #19 on: February 26, 2018, 09:27:07 AM »

The major thing that seems to be missing from the article and their web-site is the cost. So it wasn't clear to me whether I was supposed to think that this means I should no longer have an Inkjet at home, or if it was a low-cost better quality alternative to Blurb, or...

No, it's not "missing from the article" in the sense of AWOL :-)  - I did say I was not covering commercial aspects, as all that is on their website and not the focus of my interest in reviewing the product.
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Mark D Segal (formerly MarkDS)
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