# How to use the !PrintTool Application

click here for information on selecting a palette file

|  | Clicking on the application icon will open the following window. This window is where you enter the palette number that represents the file that you wish to edit. Clicking on the "Open Palette Directory" button will open the directory that holds your selection of palettes.

Once you have entered a palette file click edit this will lead to the following window. For the purpose of illustration I am using palette 14 ( this is used by canon printers ). Clicking on the edit button opens the main dialogue window as featured below;
This window is the main dialogue for the correction of the palette. It is designed to isolate all factors that control colour. Allowing you managability over the quality of your printouts. For the more advanced user there is the option to increase this control. This option can be selected by clicking on the "Advanced" button at the botton of the dialogue box. Help on the advanced option. This advanced option allows control over aspects of printing that are not often used within normal operation.

### Saturation

- Brightness; This is a value used to determine the overall density of ink placement. Values greater than 1 will begin to decrease the amount of ink placed on the page. Similarly values less than 1 will increase the amount of ink.
- Contrast; This value will effect the percieved difference between the darker and lighter shades of a colour. A value greater than 1 will increase this distance, resulting in more definition at the expense of colour information. Less than 1 will increase overall flatness.

### Cartridge Type

<lh>Some cartridges only use colour inks, others include black. The reason for this is that in theory black is the a mix of all the inks in a "colour only" cartridge. This is not always the case so some cartridges provide black as well. However, for the calibration of colour information it is usefull to calibrate on colour only. So for the reasons of calibrating colour, we suggest that you first calibrate on colour only, even if your cartridge provides black ink. This decreases the complexity of colour balancing. In the final stages we turn our attention to the relationship between black and the other colours. At that point if your cartridge has no black ink you have finished calibration.</lh>

### Levels

<LH>This category primerily effects the colour inks. With this section in optimal settings the colour inks will truly represent, to the limits of inks and paper, the percentage of intensity indicated in the original image.</LH>
- CMYK Gammas; This is general bias that is given to the inks as a function of its intensity. As such inks at extremes ie 100% or 0% have little effect, where as inks closer to the 50% mark have the greatest bias. The reason for this is derived from the method of printing and the tendency for inks to appear darker than their actual density. The aim of these values is to derive a linear increase in the appearance of inks. ( ie 50% of an ink looks half as intense as 100% ) An increase in this value decreases the intensity in the mid regions.
- Maximum Single Ink; This is a value that marks the point at which the amount of ink on the page exceeds that which is absorbed. This value is dependant on the quality of the paper. Having it set too high will cause ink to run and the image to appear on the reverse of the sheet. Too small a value will not utilise all of the colour range.
- Maximum Two Ink Combination; When two inks are used in a region the effect is to add the two amounts of ink together. However, this is not the case as the prevous ink have had a chance to dry, and absorbed more, before the second is applied. For this reason this is value can be adjusted in the same manor.
- Maximum Three Ink Combination This is an extention of the previous categories for the application of three inks. This is the three colour inks

### Colour Biases

<LH> Red, Green and Blue, the primary colours used by your monitor, are represented by printers as equal mixtures of Megenta/Yellow, Cyan/Yellow and Cyan/Meganta respectively. By using these colours the printer can represent most of the colours that you can see on your monitor. As such 10% of red is 10% of magenta + 10% of yellow in the same area, allowing for corrections of ink combinations and gamma. However due to the biasing of inks and papers this may not always be the case. It is for this reason that we allow for the ability to adjust output biases. A positive value will increase the amount of the mentioned colour relative to the other. Usual values are between +/-15. </LH>

### Grey Level Replacement

<lh> This section is only important if your cartridge contains black ink. Black is represented in colour cartridges by a equal mixture of all three colour inks. However this in most cases has a tendency towards a browny colour. To overcome this manufacturers use pure black inks replacing the usage of the three inks combined. The problem, adressed here, is the smooth transition between the blacks represented by three colour inks and pure black.
At the darker end of the scale, where more ink is used, it is easier to disguise this transition. Where at the lighter end it is more difficult. As a result the usual method is not to do any form of replacement until a threshold value and then in a graduated manor as the intensity is increased. In this window we always tend toward 100% replacement at 100% of three colour black. The advanced window has the ability to adjust the maximum replacement value, this is however rarely done.
This section is represented in the graph below. This shows the requested intensity against the plotted intensity. The grey curve represents the three ink black. Notice that it maps 100% desired intensity to about 80%, this is due to the maximum ink levels. There is also a slight curve, this is due to the "gamma" curve. Under this is the red curve, this is the amount of ink that is NOT to be plotted. This results in only a small portion of the coloured inks being used in a dark areas. Under this is the blue curve, this is the amount of black ink to be added to replace the coloured ink that has been removed. </lh>
- CMY deletion value at 50% This is the amount of three ink black that is removed relative to its intensity. This is expressed as a percentage of the output intensity. This is represented in the graph above as the higher of the two horizontal green lines (dashed), the value here is about 40%.
- Grey replacement value at 50% In the same way this defines the curve of black ink replacement. In most cases black ink is more black than three ink black, this means that the black replacement value may be lower than the CMY deletion value. This is represented as the lower horizontal green line, about 30%.
- Start replacing at: This is the threshold value, it is at this value that black replacement begins. It is also the zero point for the curves defined in the above values. This is where the two curves meet the horizontal axis.

## Button Usage

- Advanced This opens a more advanced window for editing palettes.Click here to for help on this.
- Clear This clears the values, replacing them with default or neutral values
- Walkthrough This is an interactive palette calibration where a series of patterns are printed. Each pattern highlights an aspect of the palette, in a progressive way, so as to work from default values to a tuned palette.Click here to for help on this.
- Refresh This resets the values in the dialogue box from the file.
- Cancel This closes this window without saving the palette file. It has the same effect as clicking the close window button.
- Save This replaces the palette file with one with the current settings.

## Exceptable values

These values are those that are accepted by the application. Values outside this range will result in an exception and the closest value will be used.

Element | Minimum | Maximum | Default
--- | --- | --- | ---
Brightness | 0.1 | 10.0 | 1.0
Contrast | 0.1 | 10.0 | 1.0
Gammas | 0.1 | 10.0 | 1.00
Maximum Ink Values | 10 | 100 | 1.00
Colour Biases | -50 | 50 | 0.00
Grey Level Replacement Values (at 50%) | 0% | 50% | 50%
Start Point | 1 | 50% | 5%