Sorting Through The Papers

Paper has always been a media of major significance.  Artist and scholars alike preferred drawing, painting and writing on paper as opposed to chiseling on rock.  Due to the overwhelming popularity of the product much time and research has been devoted to it over the centuries.  Arches, one of the oldest paper mills, has been manufacturing its most popular watercolor paper in the same French mill since 1492, the year Columbus discovered America.  Now with the advent of digital printing, many things about paper formulation have had to change, improve or be modified.

One of the qualities we have had to become concerned with is the opacity of the paper.  How see-through is a particular paper?  The higher the opacity, the less that printed text and images will bleed through to the other side.  This is especially important for double-sided printing. Inkjet photo papers have a relatively high opacity (94-97 usually) compared to ordinary inkjet or laser papers so bleed-through is less of a problem with these papers.

How bright is bright?  In terms of paper, there are many different levels of brightness.  Brightness is now standardized so it may be expressed as a number from 1 to 100. The multipurpose bond paper used in copy machines and desktop printers generally has a brightness index in the 80s.  Photo papers are usually in the high 90s.  Not all papers are labeled with their brightness rating; therefore, the best way to determine brightness is simply to compare two or more papers side-by-side.  In general, test photos appeared brighter and the colors clearer on the papers with higher brightness ratings.  With matte finish papers, the higher brightness made a marked difference.  There is less variation among the gloss finish papers.  The term whiteness is often used in place of brightness, but when speaking of this category, brightness is the correct term.  Whiteness should be relegated to speaking of the base tint or color of the paper so as not to confuse color with brightness.

Individually photo paper appears quite white in color.  But placed side-by-side, white papers show a range of colors from very bright cool white (bluish) to a softer, warmer (reddish) pale ivory white.  Technically, the more blue light reflecting off the surface, the brighter and whiter the paper appears.  For ordinary usage, the best measure of brightness is your eye and mostly the appearance of your image on the paper.

The brighter and whiter the paper, the brighter and lighter the printed images.  The image colors on the other less bright papers are noticeably darker when viewed side-by-side.  For the most part, images on the brighter white paper looked more vibrant and alive.  However, some colors that were already very light in the original image were in danger of appearing washed out on the whiter paper and should be well controlled when printing.

Even when the paper manufacturer supplies a brightness rating, the true test is how your images print on that piece of paper.  And, as you can see in the tables, whiteness is in the eye of the beholder.  Don't be misled by terms such as "Ultrabright."  Some paper distributors use that term, for example, despite a brightness rating in the low 90s.  Additionally (and to confuse matters further), your photo and your printer play a role in the results achieved with the same paper, but with different inks or printers.  You can't always trust the numbers.  Your eyes are your best judges of which paper works best for you.  Experiment to find the best brightness of paper for the bulk of your photo printing needs.

The weight or thickness of the paper is a matter of concern for the digital photographer as well.  Photo papers are heavier and thicker than typical multipurpose papers.  This thickness is necessary to accommodate the greater ink coverage typically found in the printing of photos.  The weight of paper may be expressed in pounds (lb) or as grams per square meter (g/m2).  The bond papers, which include most inkjet photo papers, are found in the 24 to 71 lb (90 to 270 g/m2) range.  If you see photo papers listed with weights of 110-145 lb., these are probably text weight papers, rather than bond weight. Text weight of 110 lb is approximately equivalent to 44 lb bond. These papers are all noticeably more substantial than the typical 20-22 lb inkjet papers used for everyday printing.  The difference in feel and appearance between the tested 69 lb and the 44 lb papers was noticeable but not significantly so. The 41 and 36 lb papers do feel lighter, flimsier.

Tested Photo Papers by Weight

• 68 lb Epson Premium Glossy Photo Paper
• 44 lb Epson Matte Heavyweight

As you can see, the descriptive term "Heavyweight" does not necessarily mean it is heavier than other photo papers.  In the case of weight, the numbers are what really count.  However, the caliper or thickness is an even more telling number.

Caliper is a descriptive term for measuring the thickness of paper.  Caliper is expressed in thousands of an inch or mils.  The caliper or thickness of the tested photo papers ran from 6 mil to 10 mil although some photo papers may be half as thick.  Thickness can affect printing if the paper is too thick to easily pass through the printer.  7 mil is a nice paper thickness that doesn't rip too easily and 10 mil is thicker and even harder to rip.  Photo papers are significantly thicker than regular non-photo papers and the papers of 9-10 mils feel more substantial, less flimsy.  In general, higher caliper papers usually are higher in weight than a low caliper paper, although this doesn't always hold true.

Tested Photo Papers by Thickness (Wt. in lbs)

• 10 mil (68) Epson Premium Glossy Photo Paper
• 9 mil (44) Epson Matte Heavyweight
• 9 mil (52) Epson Photo Paper

In comparisons, weight and thickness had no noticeable effect on printed image quality, as long as the correct paper profile was selected during printing.  It was mostly a matter of how each type of paper felt in the hand.  Heavier, thicker papers feel more substantial.  None of the photo papers experienced any of the "rippling" from heavy ink coverage that is found in non-photo papers.

The final result is that heavy weight paper can lend an aura of importance and seriousness not found in flimsier products.  Thicker papers hold up well when there is heavy ink coverage.  However, some printers may not handle thicker papers well, especially if the printer doesn't have a straight paper path.  Choose a paper that "feels" right to you and will work with your printer.

The finish or surface texture is important to most digital printmakers.  This is usually the defining point to their photographs and this is where the most research has been concentrated for inkjet printing papers in the past couple of years.  Beautiful old fine art papers, such as the venerable Arches watercolor paper, are non-coated.  This means that an uncoated paper has no additional surface preparation added to the original paper base.  Fine Art Papers have a base that is made, traditionally, of cotton and / or wood pulp fibers.  Other features that might make it a 'fine' paper are being acid-free or acid neutral, made from a high percentage of 'cotton rag' fibers, a nice texture, and so on.  A normal (not 'fine') paper may be made from wood pulp that contains lignin and other nastiness that can degrade and later discolor.  The presence of wood pulp does not necessarily indicate a bad thing, as it is apparently possible to remove lignin and make the paper-base stable.  Acid free is important to the longevity of the paper.

Without a proper treatment for holding inkjet inks, a surface coating of the paper base, traditional fine art papers are something of a danger-zone when it comes to utilizing them in the inkjet arena.  You will gain all the excellent qualities of the paper, but the inks may not behave well in the paper, so it's use may be risky.  The immediate problem is that of dot gain.  This is when the ink droplets strike the paper and sink into the paper fibers and bleed outward to a larger dot than intended by the printer and software.  The dot gain forces the image to become soft or blurry looking and color brilliance is diminished as the ink spreads out.  While the uncoated Fine Art Papers look and feel nice, they require specially made ICC profiles for satisfactory usage.

We have determined that the way the paper is made and coated determines its performance characteristics. The diagrams below show a cross section of the three different papers and underneath we explain what the differences are between them.

The first paper we will examine is the ‘Resin Coated’ paper.  This is a paper very much like the typical darkroom photo paper in both look and feel.

- Epson Premium Glossy Photo Paper
- Epson premium Luster Photo Paper
- Ilford Classic Gloss
- Ilford Classic Pearl

PLUSES:

• Your images will last because the paper has good light stability.
• As the resin-coated base is the same as that used for traditional photographs it gives your images a real "photographic feel".
• The base of your images won't ripple if they get wet, like normal plain paper, as it has a resin coated base.
• The paper is resistant to tears and kinks.
• Your images will keep their glossy appearance longer due to the fact that the ink is absorbed by the polymer layer and not the paper base.
• Your images will be protected against abrasion because of its transparent polymer layer.

MINUSES:

• You may need to alter your printer settings to a slower mode as the layer absorbs the ink more slowly (please refer to your instruction sheet for printer settings).
• The top layer is not entirely water resistant and the degrees of water fastness may vary from brand to brand.

- Ilford Smooth Gloss
- Ilford Smooth pearl

The paper will feel slightly sticky or squeaky to the touch, and bending the corner will give you a slight crackling sound.

PLUSES:

•  Instant dry
•  "Out of the box" product.
•  Can be handled immediately after printing.
•  High degree of water fastness.
•  High speed printing modes can be used.
•  Heavier base weight gives it the feel of a real photograph
•  If displayed in a frame or laminated, the prints will last as long as resin coated paper.

MINUSES:

• All nanoporous media suffersfrom "gas fading"  to a certain degree.

Cast coated papers are normal inkjet paper, or fine-art inkjet paper, with an additional layer added after the paper-base has been made. The coating contains special chemicals that (as well as being designed to enhance paper color) are designed to accept and hold the ink droplets in the surface of the paper.  Often, ceramics are used for this coating, titanium for whitening, etc.  Each manufacturer has their own coating so again, caution is advised. The coating is squashed into the paper base by heated rollers, which apparently results in a glossy effect.

These papers may well have the characteristics of a fiber paper, with the additional 'qualities' that one side will have a slightly different feel and color to it than the other (unless it's double-sided coated).  It should be pointed out that cast-coated papers could be glossy.  Apparently, a characteristic of these papers is that the surfaces are easy to damage with a fingernail, and a drop of water on the paper will be absorbed quickly, but the paper will bulge irreparably.

PLUSES:

• Your prints will dry quickly as the ink is absorbed into the paper base.
• You can use the paper on a wide range of printers due to the minimal interaction between the ink and the receiving layer.
• Even large particles (ie the pigment used to make black ink) will be absorbed into the paper.

MINUSES:

• Your prints will not last as long due to poor light stability.
• Your prints will not feel like real photographs due to the paper base.
• If you use a lot of ink in one given area to create your image i.e. a black background the backside of the paper will ripple.
• Your prints will lose their glossy look quicker because the ink is absorbed directly into the paper pulp.
• The paper is not tear-resistant and is prone to kinks.

This type of coating is becoming more and more popular, especially with glossy Resin-coated papers.  The inkjet receiving layer on top of the resin is specially constructed to seal-in the ink droplets.  This helps prevent gas fading and in addition may help control ink-droplet-mixing once the droplet has hit the page.  Both of these issues can lead to longevity matters (especially for dye inks) that can be seen as an advantage.  This may also be associated with 'gelatin' coatings.  However, rumor has it, that swellable polymer papers may create a problem with metamerism, even for inks that do not normally suffer from this.

These papers have a plastic like feel to some people, like a photo from a 1-hour developing service.  Bending the corner of the paper will not leave a mark.  A drop of water on the paper will not be absorbed quickly, but when it is the paper will retain its original appearance.

MINUSES:

• Leaves colorants exposed to the air to some extent, therefore 'gas fading' is possible.

 

For More Information:

For more information on Epson ink and paper compatibilities click here.
http://www.pictureline.com/digital/dinkjetsupplies/depson/inkcompatibility.html

For more information on Ilford ink and paper compatibilities click here.
http://www.pictureline.com/digital/dinkjetsupplies/dilford/ilfordclassicpearl.php
see Ilford Galerie printer profiles, Fact Sheet, How to Choose, and printer settings guide.

Pictureline stocks the full line of Epson and Ilford papers, generally in sheets and rolls.

Submitted by askRodger@pictureline.com