Inkjet Receptive Coatings

            What impacts one’s decision is ultimately durability and color quality when purchasing a fine art printing substrate. A large portion of these two factors is determined by the inkjet receptive coating that sits on top of the substrate and absorbs the ink. The ink must be able to penetrate and bond with the coating in order to have high quality image quality and long lasting durability. There are three major parts of an inkjet coating: the pigment, binder and additives.

            The pigment is usually a porous, viscous composition of silica pigments. Silica pigments have silanol groups that work to absorb and separate the solvent from the ink. The amount of silanol groups is determined by the pH levels of the silica, higher pH equals less silanol groups. It is also a highly viscous substance that is apt to crack if not combined with a binder.

            Binders function in a coating is improve the strength, hold the colorant at the surface and improve the smoothness of the coating. As silica is a highly viscous substance and combining it with a polymer makes it more stable. One of the most commonly used polymers as a binder in the industry is PVOH or PVA, which is a hydrolyzed version of polyvinyl acetate. This polymer works the best with silica in its partially hydrolyzed state, the OH molecules present in the polymer do not shrink as much when it dries which creates more stable color saturation and prevents cracking.

            Prevention of cracking is another reason binders are used, while pigments are great at absorbing the solvent and being porous, they are not the most stable compounds. Combining them with polymers enhances the overall durability of the combination and color accuracy. By itself silica would be able to absorb the ink but would not be stable enough. However, it is important to consider the molecular weight of the particular PVOH polymer used in the combination. If the molecular weight is too low, it will fill the holes in the silica and then the ink will not have a place to bond. On the other hands too high of a molecular weight lowers the viscosity to the point that it cannot work as intended. It is best to use as low of a molecular weight as possible, where the PVOH does not fill the gaps in the silica. Binders reduce the porosity and absorbance of a pigment, but increase the strength and durability.

            Additives help enhance the chemical attraction between the inks and coating. Many of the dyes used in inks have ionized compounds and adding a catatonic additive helps this bond with the coating. The coating would be functional without additives, however, they enhance the final properties of the coating. They can also play a role in altering color composition by changing the wavelength of reflected light.

            Together these components help filter the dye or pigments from the solvent and adhere these colorants to the binder. The porosity of the pigment separates the solvent from the colorant and isolates the colorant. Utilizing a coating provides superior ink adherence over uncoated paper or canvas. Manufacturer’s can create a product which has significantly improved qualities over what was previously available. A previous problem with coatings for canvas was that they cracked if the canvas was ever bent. This was solved with using the correct binders and additives, improved bonds between the pigments and other particle has largely eliminated this problem from printing. 

            Chemically evolved inkjet receptive coatings are used on many common substrates such as paper and canvas and understanding the composition can help you make an educated decision about what is the right product for your

A little history on Fine Art Reproduction

       Prior to modern day Giclee, Lithography was initially created in the late 1700’s using plates. However the high cost of producing custom plates and its limiting use of only 4 inks: Cyan, Magenta, Yellow and Black, made if highly inefficient. And impossible impossible to reproduce bright colors found in original works of art.  

Example 1: Lithography process 

     In the late 1900’s Iris printing system was introduced to proof commercial pre-press before being produced on a plate—allowing revolutionary proofing devices. As this method became recognized, big name companies such as HP and Epson accelerated research for improvements to the printing system, soon enough a new breed of printers emerged. These new machines surpassed the traditional IRIS printing system by allowing the use of up to 12 inks compared to the traditional 4 inks—resulting in stunning works of art.

                                    

Example 2: Giclee Print 

What does the future of fine Giclee hold? You can expect improvements in speed and color ranges, and present trends suggest prices of hardware and Giclee printers might decrease.

Need an eye, for color? Check out the I1Pro 2 spectrophotometer!

      That's spectrophotometer: spec·tro·pho·tom·e·terˌ

      Noun

An apparatus for measuring the intensity of light in a part of the spectrum, esp. as transmitted or emitted by particular substances.

Professional Color Management

The new standard of perfection for Color Perfectionists looking for an affordable, professional-level spectral color measurement solution offering display, monitor and printer profiling. Calibrating your printers, monitors, and scanners are essential for print color accuracy. It reduces time and materials wasted while proofing your prints
 

The i1Pro is a ridiculously easy to use tool that will get you professional results right out of the box. We here at Canvas and Paper Warehouse (and our sister companies) have benefited greatly from the i1Pro system. From scanner and printer profiling to even color correcting our computer monitors!

What is the i1Pro 2 system?

When you open the exquisite black case, you'll notice what I like to call the “Monocle” the i1Pro 2 spectrophotometer, along with assorted accessories: Certificate of Performance, USB Cable, Software DVD, User Manual, ColorChecker Classic, ColorChecker Proof, Backup Board and Ruler, Calibration Plate, Positioning Target, Display Holder, Ambient Light Measuring Head, Tripod Holder, Carrying Case, and a security USB chip that holds your software license information.

The Monocle has a solid feel to it, like a small rubberized brick. On the left side of the unit is a measurement button. The top sports a two LED indicators. These indicators assist and guide you through the measurement process.

Solid white – device needs to be calibrated
Flashing white – the device is ready
Flashing Green – Scan accepted
Solid or flashing red lights – Re-scan/Re-calibration needed


Another neat feature is the included UV lamp inside the monocle, this helps when profiling media that contains Optical Brightener Additives (OBA's) The enclosed tripod holder is used for calibrating Projector Displays. Located on the base of the Tripod Holder is a light measuring head that is used for Ambient Light Measurement. The display holder is a nifty device that allows the monocle to rest against the monitor for calibration. The i1Photo Pro 2 package comes bundled with i1Profiler. This software is easy to use and right away we understood the intuitive functions. I1Profiler operates in two modes: Basic and Advanced. In the left panel, there are 3 main options (if you’re in Basic mode): Display Profiling, Projector Profiling and Printer Profiling. Advanced mode offers a lot more options to further dial in the settings and color on your devices. On the bottom of each window, you can see the entire work flow. This gives you a good understanding of which step you’re on and what’s coming up next. Training videos are available from the software, that outline each function of the software. With that even novice users will be able to achieve great color right away.

Scanner profiling 

 

Profiling a scanner have never been easier. In the i1profiler software you simply need to select a target from the list of reference targets (sold separately). Then scan the selected target with all color adjusting settings on the scanner turned off. Once you have the scan, load it on to the i1profiler software and the software will auto target your samples. Continue forward and create a .ICM color profile to adjust for any differences in color. Just add the profile to scanner profile settings and your good to go!

Printer Profiling

We profile all of our digital fine art paper across multiple printers, including our Premium photo paper. In basic mode the software lets us generate 3 different chart sizes from: Small (400 patches), Medium (800 patches) and Large (1600 patches). In advanced mode you can generate anywhere between 400- 6000 patches. There are great advantages to using a larger number of patches, namely the color reproduction, gradation, shadow and highlight details are significantly improved.



The included Backup Board has a built in clip on the top that holds the printed out chart in place for larger tabloid prints we've found it helps to tape the lower section as well. The included ruler helps the monocle slide effortlessly across the Backup Board letting you scan thousands of patches in minuets.
The profiling software allows us to measure each row in each chart with a single or dual scan. In single scan mode, the i1Pro measures No Filter, UV-included measurement that is equivalent to ISO type M0. In Dual scan mode, the i1Pro uses UV-included (type D50); equivalent to ISO type M1, as well as the UV-excluded, or UV cut measurement that is equivalent to ISO type M2.
We used the large, 1600 patch set to profile our Professional photo paper, Inkjet canvasses, and , Digital fine art paper. The results were stunning. The prints looked crisp; colors were well saturated and reflected what we saw on the screen perfectly. The new profile resulted in sharper, more accurate images.

Monitor Profiling

The process of Display Profiling is quick and easy, simply select your display, white point and luminance. In this window you can also select the option to use the Ambient Light Control. If you select the Ambient Light Measurement option, i1Profiler will display instructions on how to attach the special plate that makes the measurement possible.

The i1 fits well in the Display Holder and the units fit well over the monitor. The profiling process takes about 10 minutes. During that time, the software displays a series of different colors on the screen. i1 measures what values are being displayed and builds the profile.
After the profile is saved, a 3D model of the color space is displayed. You can also see a preview of some test images to compare the before and after results. Seeing these results shows the importance of calibrating your monitors and doing so on a regular basis. Keep in mind, all monitors “drift” over time. In order to keep your images and prints consistent, it’s important to calibrate your screen on a regular basis. A very nice option in the software is an automatic reminder that will prompt you to re-calibrate every 1, 2, 3 or 4 weeks.

Article on Paper Making Part 3

Machine versus Handmade

There are essentially three methods of creating paper, two are mechanical and the third is by hand. The two machines you are most likely to hear about are called the Fourdrinier and the cylinder. Occasionally you'll find the cylinder process referred to as mould-made. This is a little confusing for the average watercolorist who would probably assume mould-made to automatically mean handmade.

The Fourdrinier is a high capacity machine with a screen belt, continuously supplied with pulp from a headbox. As the conveyor moves away from the steady stream of spreading pulp, the shaking belt forms the paper, while suction drains the excess water from below. In short order the belt ends, depositing the juvenile paper on another belt to be whisked off for pressing and drying. After being cut into serviceable pieces, it's packaged and sent to your art supplier.

The cylinder machine, which makes mould-made paper, is a bit different ... at least at the beginning of the process. Like a ferris wheel, half submerged in pulp, this horizontal screened cylinder continuously turns, forming a sheet of matted pulp on the screen's exterior. The endless sheet of "formed" paper is deposited on a belt and moved through the drying process with the same haste as in the Fourdrinier procedure. The cylinder machine offers two advantages. First, a thicker sheet of paper can be formed, and second, the grain isn't as pronounced.

Grain, refers to the microscopic alignment of pulp fibers. The Fourdrinier machine, with its speeding belt produces the most obvious grain alignment even though the manufacturer tries to counteract this by shaking the belt as the sheet forms. The cylinder has a slight edge in reducing grain, if it's slowed down. Too much grain can make a visually distracting surface pattern. Grain also causes the paper to expand more in one direction than the other, that can cause problems while painting and framing. Unfortunately this is the price one must pay when using inexpensive, high production, machine-made paper.

Fig 9 20: In a dramatic move, the mould is raised from the vat with excess pulp flying to all sides. This grand gesture is called, "throwing the pulp."

Watching paper made by hand is far more fascinating. The papermaker uses a mould which is a flat sieve of brass wire mesh supported by a mahogany frame with tapered ribs. On top of the wire mesh is another frame. This one, called the deckle, is removable and creates a dam retaining the slushy pulp as the mould is lifted from the vat. The thickness of the deckle frame controls the depth of the pulp layer, and ultimately, the weight, or thickness, of the paper.

To “cast” a sheet, the papermaker dips the mould into the vat of pulp scooping up a load within the retaining walls of the deckle. This is not a delicate move ... it's not meant to be. The excess pulp is removed in a grand motion called "throwing the wave." (See Fig 9 20)


  Then the papermaker, holding the frame level, shakes the mould side to side and back and forth until much of the excess water is drained. This action interlocks the cotton fibers and minimizes grain. In papermaking jargon, the sheet is now formed and this is when hydrogen bonding begins. (See Fig. 9 21)

Fig 9 21: The papermaker shakes the mould, excess water drains away, and cotton fibers interlock molecularly to form a sheet of paper.

After more water is allowed to drain, the deckle frame is removed. The first thing you notice is a thick layer of shaped pulp left behind on the mould. (See Fig 9-22.)  Then you notice a thinner layer where the deckle frame rested. This is the pulp that seeped under during the dipping and shaking. It's the deckle edge, and a true piece of handmade paper has four deckles. That's not to say a cylinder sheet of paper might not claim four deckles, but how they achieve it is certainly not in the time honored tradition of the craft. Machine made paper can only have two real deckles or fewer.

Fig 9 22: Here, you can see the deckle frame being removed from the mould. The small amount of pulp that seeped under the deckle frame, during the prior action, fittingly enough, is called the "deckle edge."

The next step is to couch the formed sheet. This word derives from the French verb coucher meaning, to put to bed between blankets. If you want to sound like you know what you're talking about, you pronounce the word "cooch." During this step the sheet, which is still saturated with water, is turned upside down and transferred to a felt pad. When you see this, your first thought is, "That's going to slide off the mould and create a very sloppy mess." Fortunately, the water's surface tension maintains the sheet’s adhesion throughout the move. (See Fig 9-23.)