IMPORTANT: Sales of
POSTERS are suspended. The status will be reviewed in 2013.
A reference for artists, color enthusiasts, and color scientists.
Note: This poster was previously available in Standard and Deluxe Editions. It is now available solely in the Deluxe version, which is printed on a gallery grade paper, and which shows more patches.
Note-1: The number of patches depends on the gamut that can be achieved by the ink-paper combination. See the
illustration below for an example of the extent of
the 5G patches, and the
Poster color accuracy section for additional
Here is a zoomed image of the poster, to which we have added scales, in inch and cm, to show the patch size. Each patch is identified with its Munsell notation. The background is a light grey with a nominal 89% lightness (lightness is the L* of L*a*b*).
Poster color accuracy
There is no point in producing a poster about a color system if the colors are not accurate. Defining "accurate" is a tough job though. What is accurate for a person will be rejected by another. Accuracy also depends of the end use; for example, in advertising, company logos and elements of products packaging often have precise colorimetric requirements. Since the accuracy requirements are higher than what can be obtained with blends of the primary printing inks (usually Cyan, Magenta, Yellow, and blacK, i.e. CMYK), additional inks of the exact color (called spot colors) are used to print these elements. In traditional printing, spot colors require a separate printing plate, at an extra cost, and it is not difficult to see why the number of spot colors is usually few. Here we have a poster which would ideally require thousands of spot colors! This could be done if we produced each patch individually, but is definitely impossible when printing all colors simultaneously. So we know from the start that we will need some compromises, but where do we draw the line for accuracy? Let's make a small digression which starts with the raw data.
For this poster, the raw data is defined by the "renotated" Munsell data (discussed in the next section), which is XYZ (CIE1931) color coordinates of Munsell colors as measured with Illuminant C, a now obsolete daylight illuminant relatively close, but not equal, to the more modern D65. The data is first converted to Illuminant D50 in order to be compatible with the ICC Profile Connection Space (PCS) which is now ubiquitous in image processing. In a second operation, an ICC profile is used to convert between the D50 data and the printer colorimetric space.
Selecting a perceptual rendering in the second step would maximize the number of colors that can be "perceived" as correct when printed; however, the perceptual rendering shifts ALL colors to maintain a certain relationship, with minimal regards for individual colors' accuracy. What is required here is an Absolute rendering, where we strive to reproduce the colors precisely, with the knowledge that this precision will fall dramatically when the colors are out of the printer's color gamut, defined by the range of colors which are possible to reproduce with specific printer's inks laid out on a given paper.
The Munsell Color System can describe all visible colors; unfortunately, no printing system or mix of pigments can reproduce such a gamut. This means that all representations of the Munsell system, either in poster form or with large individual patches stored in 3-ring binders, can only show a subset of the system colors. However, with an ink-jet printer, we can "play" with the ink/paper combination in order to improve the gamut; alas, there is no great freedom in this game. Once you select a printer, this usually fixes the ink choices to sometimes two or three ink-sets, but most often only one, which leaves only the paper selection as the variable. On the plus side, there are more companies offering printers with high-gamut inks than ever before. Still, once a printer is selected, you can only play with the paper to adjust the gamut. Regrettably, some printer drivers are designed in such a way that it is difficult to use third party papers, even if you generate an ICC profile for them yourself, further limiting a quest for large gamut printing.
With the above in mind, we reviewed the market for mid-range professional printers, where mid-range applies here to cost and not print quality, since all the printers reviewed are top-performers in this regard. Our short list was essentially Canon, Epson and HP, and we selected the HP Designjet Z3100 for the following reasons:
Important: This is not a review of the printer, and it is certainly not a global rejection of all other printers, which all have great features! For reviews of the HP Z3100, we suggest: Michael Reichmann's review on The Luminous Landscape as well as his comparison with the Epson 9800; and Uwe Steinmueller's review on Outback Print. You will also find other links to reviews in this unofficial site for HP Z3100 users.
At this point, we had data, a method to process it, and some hardware to show it. As can be inferred from the preceding paragraphs, our goal was to maximize the number of printed colors from the Munsell Color System, with a hardware selection which places emphasis on accuracy and stability.
Now we can go back to our original question: Where do we draw the line for accuracy?
Like many things in life, and particularly for this task, we have to live in a grey zone! We first decided that this poster was not designed for quality control purposes, if only because each color patch is too small to be judged against a test sample. On the other hand, a lot of time was spent making sure the patches would be printed with "accurate" colors. We then decided that we would print only the patches that are considered "in-gamut" as judged with Photoshop's "Preview" tool. Because the technical details of this Photoshop feature are not documented, we made numerous print tests where we measured the patches, particularly the ones at the gamut's edge, and compared them to the reference data. We also compared the Photoshop results with PatchTool's "Clip check", which can predict if a color is within a profile's gamut, and if not, by how much. As well, we visually compared the in-gamut patches L*a*b* positions in 3D relative to the 3D gamut shape derived from the ICC profile. Overall, we measured that the Photoshop selection threshold was somewhat flexible; the DeltaE (CIEDE2000) of out-of-gamut colors which are on the gamut's edge varies between 2 and 7.
Please note that the measured color differences combine the printing error and the measuring instrument's accuracy, and, more importantly, that these colors are outside the gamut as flagged by Photoshop, which means that they were not retained for the poster. In short, this is where we drew our line. In practice this means that the absolute color accuracy is slightly less for some colors with maximum chroma, on the gamut's edge, while being consistently good within the gamut volume. But by how much you may ask? At this moment, we evaluate that the average error is around or lower than 2 DeltaE (CIEDE2000), as measured on a black ISO background.
Munsell Color System info
Originally developed in the early 20th century by the American artist Albert H. Munsell (1858-1918), this is the first widely accepted color order system. In this system, colors are identified with three parameters: Munsell Hue, Munsell Chroma and Munsell Value, or Munsell HVC for short; they are presented in the form: Hue Value/Chroma.
The Munsell Hue is separated in 10 hue ranges (please refer to the illustration below). For each hue range, there is a major hue located at the range center. The major hues are Red, Yellow, Green, Blue and Purple, as well as the five hues located between them and named by combining the names of the hues on each side. For example, the hue located between Yellow and Red is called Yellow-Red, instead or Orange; this naming convention minimizes the number of color names one has to deal with.
Each hue range is further divided in 10 sub-zones defined by
11 radii labeled from zero to 10. The major hues are labeled 5R, 5YR, 5Y, 5GY,
5G, 5BG, 5B, 5PB, 5P, 5RP. The color circle is, in effect, separated in 100 hue
segments where each hue separation is perceptually uniform. A zero to 100 number
can be used to describe the Munsell Hue but it is seldom seen (the zero is at
10RP, the numbers increase when going counter-clockwise, up to 100, also at
The illustration below presents samples at specific value and chroma intervals for the 5R hue. Only samples that fall within the sRGB gamut are shown; this explains why the maximum chroma is different across the value range. The most saturated sample in the illustration is "5R 5/18". Please note that not all chroma intervals in the illustration represent unitary steps; also, this illustration is not a sample from the poster.
A great tool to learn and practice the Munsell system is The New Munsell Student Color Set, which combines a color-primer book with small color chips; this tool is produced by Jim Long and Joy Turner Luke (Fairchild Books and Visuals (2001), ISBN 1563672006).
The Munsell Color System is also supported in other BabelColor products. With BabelColor CT&A you can select amongst thousands of pre-determined Munsell colors in the built-in Color Decks (color databases), and find the equivalent L*a*b*, L*u*v*, and RGB coordinates (for virtually any RGB space). You can also obtain the Munsell equivalent (with fractional accuracy) for any L*a*b*, L*u*v* or RGB input, either manually entered or measured with an Eye-One colorimeter or spectrometer.
The posters are first rolled and inserted in a plastic bag. We roll the posters to a diameter which is approximately the size of the core on which the paper was shipped on; this helps minimize paper curl. The bag is loosely closed in order for the bag to adapt to atmospheric pressure differences; it is then placed inside a heavy-duty double-walls cardboard tube. We make sure that there is a gap between the bag and the tube; this packaging facilitates poster extraction from the shipping tube and provides extra protection against potential abuse to the tube during transit. To accommodate the above requirements, the outside tube diameter is 4 inches (102 mm).
Of course, such a packaging has an effect on the shipping cost, but we believe that a high-quality print must not be packaged like a generic paper roll.
All shipments are made from Canada. Once the poster is shipped, we send an email with a tracking number and a tracking link (Note: The tracking number may be already included in the email link). Here are Web sites you can use to track your shipment:
The Canada Post "Delivery Standards" (i.e. shipping delays) are described on this page. Here are some of these standards:
Please note that shipping delays are expressed as BUSINESS days, that they are valid for MAJOR URBAN CENTERS only, and that additional delays should be expected when there are HOLIDAYS. For example, the Canada Post "Delivery Standard" for an "Expedited Parcel" to the USA is "in as little as 6 days". We have seen shipments arriving within such a delay; however, as you have certainly noticed, there is no maximum written in their standards, and we have also seen shipments arriving in 13 to 17 business days (or almost a month!).
You should be aware that there is not much we can do once the shipment is in transit, and even Canada Post uses the same information you get from the tracking site, so we cannot provide more information to you during this period. We suggest you select to be informed by email when a "scan event" is registered; this selection is available on the Canada Post tracking page (A tracking number MUST first be entered; then look for the "Request Delivery Updates by email" link).
International orders (except USA): International "Surface" shipping, which most often means "by boat", is no longer available. We have taken this decision because of the extremely variable, and often long, delays that were encountered with this method. We have added "XpressPost International" as a new shipping method; while slightly more expensive than surface, it is much faster and can be tracked more efficiently.
Save shipping fees by ordering 2, 3 or 4 posters. Not only will you get a rebate on each poster, but the shipping fee will be almost the same as if you ordered one poster. The reason is that shipping fees, for this package, are determined primarily from the package dimensions, and the actual weight has less influence on the shipping cost. Since we use a large and sturdy tube for delivery (see the Packaging section for more info), we can insert additional posters into the tube with minimal or no effect on the shipping fee. Please note that you need to have at least one item in your cart to see the shipping fees (see the Purchasing info below); you also need to enter your address in the first step of the "Checkout" process (Note: you can cancel the checkout at this point). Once your address is entered, you can easily compare the shipping fees for 1 to 4 posters without entering your address each time.
We understand you may be anxious to receive your poster, and we appreciate your eagerness, but we can only ask you for a little patience if this happens. Of course, if the delay becomes worrisome, please contact us.
Handling the poster
We recommend using protection gloves designed for photographic applications when handling your poster, which is in fact a high-quality exhibition type print. Such gloves can be found at Gloves-Online and Talas. We particularly like the ones with PVC micro-dots on each finger, from Gloves-Online, which are a blend of cotton and nylon, and which offer an excellent grip as well as a close fit; however, you may prefer a 100% cotton glove, with a loser fit, but more comfortable when weared for long periods.
If required, let the shipping tube stabilize at room temperature before opening it; for example, wait for an hour if the tube stayed outside for a while in freezing conditions. Once removed from the tube and from its plastic bag, you should unroll the poster slowly.
Even if we roll the poster to a diameter which is much larger than what most poster resellers use, some curl may be present once unrolled. The amount of curl will vary with temperature and humidity, and extremes in each should be avoided. Most, if not all of the curl should disappear if you let your poster rest overnight on its own weight, with the printed side on top. However, you may find that, even after a day, the poster is not perfectly flat; still, this will not prevent mounting or framing.
If needed, here is a procedure to remove the curliness of the media, which is adapted from a procedure suggested by HP, the paper manufacturer.
Important: Be careful when manipulating your poster as you could inadvertently introduce a "kink" in it. You may want to practice with another large piece of paper before doing-it on the poster.
On the other hand, if you intend to have your poster mounted or framed by someone else, we suggest you leave it rolled in its shipping tube.
IMPORTANT: Sales of POSTERS are suspended. The status will
be reviewed in 2013.