HP Designjet T1100ps A0 User Manual

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The HP Large Format printers have a way to compensate for these problems: Closed-
Loop Color calibration (CLC). This process consists of calibrating the printer by applying 
a color value table, which is created by printing a color ramp for each ink and 
measuring it with an internal color sensor. 
 
Depending on the printer model, there are different ways to access this feature (see your 
printer’s documentation). 
 
Each time a printhead is replaced, a printhead alignment should be run (this is 
automatically started in most cases) to avoid image quality degradation. 
 
Please refer to the printer’s documentation to maintain it in good working order. 
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The final image is the output of the printer. It should be handled with care, ensuring that 
the ink is completely dry before using it. 
 
Please note that the perceived color is a result of the ink, media, light and air physical 
or chemical interactions, and it can, therefore, change unexpectedly when conditions 
differ significantly: direct sunlight, temperature, humidity, air contamination, etc. In 
order to avoid fading, you are recommended to cover the copy with glass or 
transparent film and not to expose it to direct sunlight. 
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The previous sections have described each of the components of a color reproduction 
system. This section talks about the interactions between these components. 
 
3.1.6.1 Color management 
 
To obtain a good color reproduction, the color definitions coming from the scanning 
system have to be adapted to the color definitions needed by the printer. For example, 
a specific green color may be reported by the scanning system as: 
 
Red: 60%, Green: 70% and Blue: 40%  
 
but can only be reproduced identically by the printer if defined as: 
  
Red: 42%, Green: 81% and Blue: 38% 
 
There is therefore a need to convert the scanning system’s RGB colors to RGB values 
understood by the printer. This conversion is done automatically by the scanning system, 
using the media profiles. 
 
						

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The media profiles define the relationship between the colors the scanning system sees 
and the colors the printer is able to print. For some printers there is a set of pre-installed 
media profiles (High-gloss Photo, Coated, Bright White, etc.). However, if you need to 
print on other media, or desire a color reproduction system that better matches your 
media, it is advisable to create new media profiles, as specified in section 3.3. 
 
A new media profile will ensure that the scanning system and the printer are 
perceptually better adapted to each other. You are recommended to create a new 
media profile every time a printhead is replaced (just the printhead, not the cartridge), 
and every time a new media type, for which no media profile already exists, is loaded 
into the printer. 
 
In addition to the always-active color conversion provided by the media profile, there 
are some optional settings in the touch screen that allow the operator to modify the 
colors of the printed output. Any modification to such settings may produce a copy that 
is not perceptually similar to the original, but may be desirable for some other reasons 
(more vivid colors, darker or lighter image). 
 
These settings are: 
 
• Lightness: makes the whole image darker or lighter. 
• Saturation: intensifies or weakens the colors. The final image becomes more 
vivid or grayer. 
• Color balance: corrects the red, green and blue of the whole image. For 
example, if the image has a yellow color cast, increasing the blue color balance 
may reduce it. 
• Black enhancement: makes all areas beyond a specified threshold of 
darkness completely black. This feature should be used when text that should be 
black appears in the copy as gray. 
• Background cleaning: makes all areas beyond a specified threshold of 
lightness completely white. It is useful when copying drawings that have a 
colored (not white) background, such as blueprints. 
• Black ink only: forces the printer to use only black ink. It is useful to avoid a 
color cast in the printed output that is produced by the use of composite black 
made from mixing colored inks. Note: the Black ink only setting is not 
available with some printers. 
• Enhance gray: converts pale colors in a color image to gray. 
 
To see these settings in action, please refer to section 3.4.  
 
3.1.6.2 Image enhancement 
 
 
						

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Image enhancement is used to improve the original image or a portion of it. The final 
image will not be an exact copy of the original but, rather, a re-interpretation of it that 
corrects some of the original’s shortcomings (e.g. stains, fuzziness).  
 
There are two types of image enhancement available in the touch screen: 
  
• Blur: smoothes the image. It is used, for example, when the original is worn out 
and has spikes or stains that you don’t want appearing in the copy. 
• Sharpen: enhances edges in the image. It is used, for example, when a 
drawing has smudged text or lines. 
 
Blur and sharpen are not mutually exclusive, and good results are sometimes obtained 
by combining them: an application example is provided in section 3.4. 
 
Image enhancement is optional and should be selected only if necessary, as the final 
image will look somewhat different from the original. 
 
 
						

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3.2 Which colors can be reproduced? 
 
The colors that can be reproduced vary between different printers and different printing 
media. At HP, we analyzed various environments and reached the following 
conclusions: 
 
• Glossy paper (such as HP Universal High-gloss Photo Paper) has a much wider 
“gamut” (amount of reproducible colors) than matte paper, such as HP 
Heavyweight Coated Paper. Typically, the main difference resides in the darkest 
tones (those found in shadow areas of pictorial images) and in the most 
saturated colors (vibrant red or blue). 
• The cyan ink is not as saturated as the cyan found in traditional silver-halide 
pictures. This may lead to problems when reproducing saturated cyan (sky blue) 
or dark blue (navy blue). 
• The darkest blacks are difficult to reproduce, especially on coated paper. 
Sometimes, the problem is to achieve the desired darkness; in other cases, the 
darkness is correct but has a color cast (green or pink tint). 
 
In any case, the fact that an original image shows colors that cannot be matched 
exactly does not mean that the copy will be unacceptable. It will depend on the relation 
of these colors to the surrounding ones and their “criticality”. If the affected colors are 
not well reproduced, but the surrounding ones are, the result is normally acceptable (the 
difference may be barely noticeable). On the other hand, when a color must be 
reproduced as accurately as possible (such as colors in a company logo) even a small 
deviation may cause the job to be rejected. 
 
For example, the following images show the non-reproducible colors for some copier 
systems and media as patches surrounded by a white square. This test has been based 
on the IT8.7/2 target provided in the scanner maintenance tool, which is a silver-halide 
picture and has been scanned and reproduced with the HP Designjet 500/800, HP 
Designjet 105x, HP Designjet 4000/4500 and HP Designjet 5500 Printer series on HP 
Universal High-gloss Photo Paper and HP Heavyweight Coated Paper. Please note that 
the result may vary if a different original, a different media type or an uncalibrated 
printer is used. 
 
 
						

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HP Designjet 500/800 with HP Universal High-gloss Photo Paper (Q1427A) 
 
 
  HP Designjet 500/800 with HP Heavyweight Coated Paper (C6030C) 
 
 
						

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HP Designjet 105x with HP Universal High-gloss Photo Paper (Q1427A) 
 
 
HP Designjet 105x with HP Heavyweight Coated Paper (C6030C) 
 
 
						

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HP Designjet 5500 with HP Universal High-gloss Photo Paper (Q1427A) 
 
 
HP Designjet 5500 with HP Heavyweight Coated Paper (C6030C) 
 
 
 
						

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HP Designjet 4500 with HP Universal High-gloss Photo Paper (Q1427A) 
 
 
 
 
 
 
						

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3.3 Guidelines to create or validate a media profile 
 
Many of the color problems appearing in the HP Large Format Color Copiers products 
are related to the mismatch between the media’s color characteristics set up in the touch 
screen and those of the real media that is loaded into the printer. If there is such a 
mismatch, colors may be reproduced incorrectly, grays may have some color cast or 
some colors may be lost. 
 
The characteristics of the media are defined in the media profile and are selected (for 
some printers) by the Media Profile setting under the Setup tab. In some printers, there 
are a number of predefined media profiles (e.g. High-gloss Photo, Bright White, 
Heavyweight Coated); however, if you are using a media type that is not included in 
the list, or using a printer without predefined media profiles, a new media profile has to 
be created. By using a media profile that does not correspond to the characteristics of 
the interaction between the printer, the media and the ink, you risk having color copies 
that do not correspond to the original. 
 
It is recommended to check the media profile in use from time to time; for example, 
once a month or when you suspect the overall system has changed its “behavior” (e.g. 
you see colors that are consistently substituted with other colors). This is done through 
media profile validation. Please see your scanning system’s documentation to see how 
to create and validate media profiles. 
 
Note: Before creating or validating a media profile, ensure that you have color-
calibrated the Scanner.
 
 
 
						

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3.4 Effects of changing default media profile settings (color) 
 
This section describes how the media profile settings act upon the image. 
 
To create or modify
5 a type of original you need to select an existing one (Photo in this 
example) and press the Tool button 
. 
 
                   
 
In the preview pane you will see two copies of the image: the bottom one is the original 
and the top one is the image modified by the settings of the selected type of original. 
Therefore, when modifying the settings you can immediately see the effect on the 
image. You will also see an asterisk (*) on the upper right side of the type of original 
name (as in the picture above), to show that some settings have been modified. 
 
If you plan to scan many originals of the same type, it is advisable to store the newly 
created type of original under a meaningful name. 
 
The following sections describe the settings that can be modified and their possible 
values. Please also refer to the values defined in paragraph 1.3 of section 2.2. 
 
 
 
 
 
 
 
 
                                       
 5 Please note that when creating or modifying a type of original, the color accuracy between original and copy can be 
compromised.