Paper Chase - Matt Black or Photo Black - Which is Best

We examine the implications of choosing either the Matte Black or Photo Black option for the Epson Ultrachrome ink set and then see how the decison affects the analysis of a new canvas material from Epson, PremierArt Water Resitant Canvas.

Ultrachrome™ Matte or Photo Black?

This is a relevant question for users of the Epson Ultrachrome ink sets on the 2100/7600/9600 series of printers.The ink is a seven-colour set with two black options, Photo Black and Matte Black, hereafter called PK and MK. The MK is preferred for all matte and art papers, indeed the Epson 4000, which carries both types by default, chooses the ink according to which media is selected.There are a number of conflicting issues to be resolved as you make the choice of which ink set to use on the 2100/7600/9600 printers.

1. Longevity data is based on MK for art papers and PK on all others. If you choose to stray outside this set of combinations you lose touch with the database.

2. Changing ink on the 7600 and 9600 results in a loss of about £45 worth of ink, dumped into the sump to flush the system. Quick changes on a daily basis are thus out of the question.

3. Dmax is improved on art papers by the use of MK.

4. MK cannot be used on gloss and lustre papers as it smudges and rubs off.

5. Metamerism can be different between the two inks, the pigment based MK has a higher metameric index on some papers.

6. There is a poor database on the effect of the two inks and print quality.

7. Some RIPs, notably the original Ilford Studio do not recognise the MK set up on the printer and hang the system.

Setting out to measure the differences between the two ink sets is not for the faint-hearted. If the differences are subtle then the test must be carefully designed, including using the same ink cartridge set, the same paper batch and the same printer settings (e.g. media type, resolution, rendering intent).

This particular Paper Chase was timely in that we were in the middle of an ink change and we had abundant supplies of the test materials.We have chosen to compare Permajet Portrait and Epson PremierArt Water Resistant Canvas.The former is our standard fine art media for which we have lots of data, the latter was the subject of this review - we got side tracked onto the MK v PK issue! Our findings are described here and summarised in graphical form acorss the following two pages.

Permajet Portrait

The most apparent difference between an MK and a PK audit image is the Dmax i.e. the maximum black density achieved. We have available a number of different materials from a number of different printers using different profiles.The data are summarised in the table below.

In summary, the main difference is in the Dmax and depends mostly on the ink set rather than any other factor such as printer, profile or paper batch/type. It amounts to a loss of about 0.2 in Dmax when using the PK ink set compared to the Mk ink set, equivalent to about 4½% in Lab Brightness terms.The difference in Dmax was unaffected by the rendering intent.When viewing the prints in a controlled light booth it was just possible to detect the difference between the two types of print but only in the deep blacks and the very deep brown landscape tone. It was necessary to have both prints present to detect the difference and it is highly unlikely that an unskilled viewer could detect the difference without the benefit of comparing the prints side by side.We found no detectable difference in the metameric index between the two prints.

PremierArt Canvas for Epson

The differences between the two inks on the PremierArt canvas are considered in more detail as part of the review of that material.However the main findings for the PK versus MK issue are as follows.

The difference in density was about 0.2 Dmax units. The difference in the metameric index was more pronounced being 1.5 for PK and 2.5 for MK. The difference was detectable by eye, the prints matched in the viewing booth but the MK biased more green in overcast daylight.

The difference in the colour values was less pronounced on the PremierArt for the hue and saturation values especially in the skin tones.T his was s lightly surprising result but it was sustained over a number of tests and is assumed to be a real effect.

The Verdict Paper Chase

For each media a bespoke profile was made using an X-Rite DTP 41 spectro and Monaco profiler. For Permajet Portrait, Smooth Fine Art media setting was used; for PremierArt Canvas,Watercolour Radiant White was used (as recommended). A resolution of 1440dpi was used throughout, with bi-directional printing turned off, Black Point Compensation turned on and a rendering intent of Perceptual. Approximately 1hr was allowed for dry down, testing showed this to be more than adequate. The standard Colour Audit test target was used for both visual and spectrographic analysis. Paper Chase

In order to avoid lapsing into subjective arm waving we compared hard data between the two ink sets.However the question still has to be posed "can you see the difference in real prints?" We viewed in natural daylight (North facing sky overcast conditions), D65 graphics illumination, tungsten light and some rather tricky low energy bulb light.The Matte Black produced just detectably darker blacks and deep browns and this effect could be seen in side-by-side comparisons.Other tones were much more difficult to detect differences in.

The verdict? If you need to keep touch with longevity databases stay with Matte Black on art papers. Avoid Matte Black on gloss and lustre finishes. For most commercial work you will find the Photo Black is adequate on both types of surface.

UPDATE FOR LIFERS

We mentioned the magazine PCPro in our editorial this issue in regard to XP service packs. In the meantime they have issued another magazine which is of great interest to readers of Professional Imagemaker.The February 2005 (Issue 124) is compulsory reading for all photographers and artist who sell their images. One can only look in envy at the resource that PCPro can throw at a topic - they put one guy on testing printers and papers for several months! Oh the things you can do when your certified circulation is in excess of 100,000 copies! Importantly they tested the printers for all the usual stuff like print speed, ink usage and cost, but then put a sting in the tail by hanging prints in the window for months on end.The data make uncomfortable reading for most manufacturers. Indeed the only one to come through unscathed was Epson and their R800/Ultrachrome ink combination (there - we told you it was good last issue!). Even Epson got a bit of flack on ink costs but HP came out worst in the ink cost derby as the 5th most expensive liquid in the world at £2.71 per ml - still less than Mrs Editor's Chanel No 5 though! On the plus side HP were commended on their fade resistance.

Combining the PCPro data and the Wilhelm Research Imaging data does not change the basic rules of play, which remain as follows

1. Pigments are more fade resistant than dyes
2. Paper quality counts for a lot
3. Mismatch the paper and ink chemistry and you are in trouble
4. Optical brightening agents should be avoided
5. Cheap, dodgy compatible ink cartridges are what they are, cheap and dodgy!

On a much more positive note, the Wilhelm imaging data for Ultrachrome inks has reached 100years plus for a number of inkjet combinations, especially if the under glass rule is obeyed. However even if exposed directly to the atmosphere (i.e. bare frame no glass) Epson canvas bagged 120 years if coated with PremierArt Spray (not the new canvas tested here, the older one). You should take care to assess the life projections on prints you make and sell, some technologies only project 4 year lives even on the rather gentle Wilhelm testing regime. Silver halide users should not be complacent either; the better inkjets are outlasting them by a factor of more than two. Some of the biggest variations occur within the emerging 6x4 desk top printers such as the Epson PictureMate. This has projected lives of 104 years but some of its competitors can only manage 4 years!

Where does the Matte Black v Photo Black issue lie in all this? Well much of the data is for art papers, which we assume, are using Matte.There are also data on black and white prints using the full colour ink set.These push some of the fade lives out to beyond 200 years and although the ink set is not specified it seems reasonable to assume that an Epson 4000 data set would use MK for art paper and PK for gloss and lustre finishes.This being the case, the matte ink seems to be outliving the photo ink but you cannot separate out other influences such as the different coating and polymer technologies in use. If you do a simplistic averaging of the data the gloss and lustre's get to 103 years and the art surfaces to 155 years.

Visit www.wilhelm-research.com for up to date analysis.

PremierArt Water Resistant Canvas for Epson

This is a new cotton polyester base material. It has a weight of 350gsm and a thickness of 52microns (i.e.½ mm).The weave is a fine Oxford twill creating a delicate "canvas" pattern in the image.The coating is a glossy instant dry type, which is water resistant. Bizarrely the information of the box outer and the inside instructions do not seem to tally.The outside claims "instant dry" whilst the inner leaflet suggest that "this media requires time to dry…". No advice is offered on which ink set to use other than the suggestion to employ a media type of Water Color Radiant White, which on the 4000 at least would call up Matte Black. A time of 24hours is recommended to allow the canvas to "cure".WE measured the audit chart after 1hour and 18 hours and noted a very slight lightening of the print, which would have not been detectable by eye. Nevertheless you should follow the instructions before framing up a print behind glass if you wish to avoid condensation. Paper Chase

In the absence of any advice on which ink to use we tried both as part of the ongoing experiments described above. While we were able to differentiate the prints by means of the spectro data we were unable to do so by viewing the prints. The differences in the look of the print according to the viewing angle far outweighed any differences in the subtleties of the Dmax values. On the spectro the differences were of the same order as those found with Permajet portrait described above, about 0.2 on Dmax of the deepest black.The difference sin the colour coordinates were far less on this material and are described in detail below.

Media Performance Overall

Overall the colour rendition of the material was superb, mimicking that contained with the new Hahnemühle material of the same weight review a couple of issues ago.The gloss finish created a rich lush feel to the print as if it were already varnished.The gamut volumes of both the MK and PK were higher than those obtained from all other canvas materials tested this year (other then the Hahnemühle) and were up by about 25%. Surprisingly the gamut volume measured higher for the PK than the MK bucking the normal trend of the volume tracking the Dmax.

Seeing is believing

Attempting to find differences between the PK and MK images was extremely difficult. By making a careful side-by-side comparison we could detect that the foliage, bluebell blue and deep browns were slightly darker. Again however, the gloss finish made changes in the viewing angle dominate the differences.

The Greys

The greyscale linearity is shown in [1] and is one of the few graphs where the difference between MK and PK can be seen.The tone scale is essentially wellbehaved with a smooth transition down to the deepest black which levels out just at the end.The blacks were blocked up below the 8% brightness mark, about 27 RGB points.There were no detectable tone cross-over in the greys and the profile mapped the greys to within 1 Lab point of pure neutral, perfectly balanced to the base tone of the media white point. For the record, the white measured -0.66 and 1.00 for Lab a and b values.There was no evidence of optical brighteners either under uv light or on the spectral trace. It is perhaps the lack of brighteners, which gives the slight warmth to the base tone - it appears very slightly cream to the eye.

The only weak tone was the first white from the spectral highlight. In common with other canvas materials we have measured there is a slight lack of differentiation by eye even thought the spectro data suggests that ink is present.You may care to push a little more ink into your highlights if you are imaging wedding dresses but you will have to experiment.

The Macbeth Colours

The overall errors in the Macbeth Chart Colours are shown in the table for the DE2000 measure, broken down into the errors in hue, saturation and lightness. The average for all the 7600 measurements hovers around 3.3 so the MK is amongst the best at 2.70 and the PK is in the running at 3.49. For a canvas these data are remarkable as they are up with the best of the gloss and lustre finishes. As with all Ultrachrome data the weakest colours are the blues, the area of the spectrum where the eye has the greatest difficulty in detecting error anyhow. Expressed in Lab terms the overall colour error averaged around 5.5 compared to contract proof standard of between 4 and 7 on the same scale - quite a result then! In terms of the actual colour error (ie ignoring the brightness errors) the reds, flesh tones, and oranges fared the best.

The Flesh Tones

The flesh tones were very accurate; in fact the average Caucasian tone of the Macbeth Chart was a minuscule 1.6 DE2000 and 2.3 Lab, just detectable to the trained eye under ideal illumination.WE show in graph [3] the result for both PK and MK.They are typically slightly desaturated with no distinct pattern in the hue bias.To all intents these are flawless skin values right across the sweep.

Life Expectancy

We defer here to the data from Wilhelm (www.wilhelm-research.com).The PremierArt media has been tested both with and without a coating of PremierArt Print Shield.This lifts the rating from 69 years to 82 years under framed glass and to over 100 years with UV filtered glass.Unframed prints have projections of 37 years uncoated and 65 years coated.The Wilhelm notes on silent in regard to the type of ink used for their tests.

Water Fastness

The media is billed as water resistant, which covers a multitude of sins.When we coated the media with DCP Giclée varnish it smeared very slightly but enough to be damaging for a print with a white surround.Great claims are made for the PremierArt Print Shield and as it was used for the Wilhelm testing we must assume that it was compatible with the canvas. Once coated the surface is extremely water resistant, certainly OK for normal wear and tear.

Conclusion

This new material in the Epson range can be highly recommended as probably the best canvas material available at the moment .You can choose either Matte Ink or Photo Black ink at your convenience, confident your clients will not discern the difference. For life issues you will have to wait for the tests to be completed.

Epson Ultra Smooth Fine Art Paper

Having managed to get our sticky little fingers on one of the few (if only) rolls of this paper in the UK we thought it only right to let you in on the secret as soon as possible. This paper was announced at PMA in March 2003 and has been available in the USA for some time and was announced with the following copy:

“EPSON UltraSmooth Fine Art Paper is a 100 percent cotton rag that is acid-free, lignin-free and optical brightener-free.The UltraSmooth base is slightly alkaline, with a 2 percent calcium carbonate buffer to preserve the alkalinity to a conservator's pH of about 8.0. Wilhelm Imaging Research has rated dark storage well in excess of 100 years, with tests still continuing. The ultra smooth surface is similar to Epson's very popular Enhanced Matte Paper, but this paper has the greater archivability required by photographers and fine artists. It also has the highest D-Max and greatest scratch resistance of any archival paper on the market.”

These are claims that demand challenging but the web is awash with rave reviews and they can't all be wrong! The base is free from optical brighteners to improve its archival properties and we note from the Wilhelm site that the life has now pushed on to 108 years (under glass), 175 years (under uv glass) for colour and 140 years for black and white prints.T he media is available in 17", 24" and 44" rolls at 250gsm. In the USA it is available in sheet form at 325gsm and 500gsm.The sheets are coated for double sided printing. So far so good then, how did we find it?

Testing

We immediately hit a dilemma.We are in the middle of testing gloss and lustre papers and had changed our ink set over to Photo Black just as the paper arrived - typical is it not? We only found a single report on the web user groups of measured Dmax, this by the moderator of the digital black and white group Antonis Ricos (DigitalBlackandWhiteThePrint@yahoogroups.com. He measured the Dmax at 1.68 using Matte Black Ultrachrome ink. Our own Dmax was measured at 1.35 using Photo Black and even allowing an additional 0.2 this does not lift the value into special territory; certainly the claims on US vendors' sites of "outstanding Dmax and exceptional contrast" are not substantiated. Paper Chase

Despite these misgiving we liked this paper a lot.You always have to accept a drop in Dmax when you print to an art paper but prints on Ultra Smooth have a very sumptuous feel to them, enhanced by the lovely, natural creaminess of the base paper.We tried printing using a bespoke profile and a canned one from the Epson web site (9600 Ult FineArt UFA1 Std v1.icc made by Bill Atkins). Both delivered prints with a slight lack of contrast and desaturation in the high intensity colours. Our bespoke profile mapped the neutrals into the base white (Lab coordinates of 0.26 and 2.04).This served the paler skin tones particularly well with a very tiny error in the average Caucasian Macbeth skin tone.The canned profile was quite heavily biased towards orange with a distinct cross-over at around 230 RGB points. For comparison we have made a detailed plot. The white starts at the base tone (i.e. no ink on the paper!) and takes an immediate excursion down towards the orange part of the plot (upper right quadrant) before drifting slowly back to the paper tone. By comparison the bespoke profile immediately sets off towards the blue territory (vertically down) before moving back to the tone of the base. In truth neither is particularly satisfactory and had time allowed we would have tweaked the profiles to correct this (relatively rare) fault.We were left pondering if the effect was the result of using the "incorrect" ink type but had to deliver the paper back before we had time to investigate. The metamerism of the image was very low, measuring 1.5 lab Delta E points (D65 to Tungsten at 50% grey) a point that would not be lost on the monochrome specialists.

We used the paper to make some prints. These confirmed the excellent skin tones and, for those pictures that did not rely of depth of the blacks, they looked superb.We did not notice any of the claimed improved scuff resistance; indeed gentled dusting of the print with a cotton cloth produced some damage. This is typical of a smooth, matte finish paper, they are quite delicate. As with many other fine art papers, they do benefit from a gentle dusting before use so as to prevent any spotting during printing. We also varnished the surface with a DCP Satin Giclée varnish. The print was reasonably water resistant to extent that only a very tiny amount of smudging occurred. The Dmax was lifted to 1.6 with a single coating and then to 1.80 with an additional gloss coat.

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