Hydra® Profiling

1. Measurement

There are 3 ways to use measurement files:

• Upload files button: opens the window to select the measurement file to import
• Measure it button: opens the Measurement Module window (see below for the Measurement Module; not available on Safari)
• Drag and drop the measurement file directly in the field outlined

Only dataset with spectral data are accepted. Adding measurements files to the list allows to select or deselect the measurements to use.

2. Channel selection

All the measurement imported in the previous step are listed with all of their channel in the Measurement files section. Each channel can be unselected by clicking on the check on top of it. The name of the channels can be personalized by clicking on it when importing strangely formatted measurement file with uncommon names. The Resulting channels are the average of each of the channel selected in the Measurement files section. It is limited to a maximum of 7 different inks.

The Reference profile list can be used to compare the values calculated of your profile with one of the profile in our database. It should contains most of the standard profiles used in the industry.

On the right part of the screen you can see a Graph representation and a Table of the numeric values.

The Graph depends on the Graph Display list at the bottom. It can show whether the Colorimetric TVI, the Colorimetric TRC or the G7® Gray Balance.

The Tone Value Increase (TVI) shows for each percent of ink (Tone Value) what is the increase of ink provided by the profile. The Tone Reproduction Curve (TRC) shows for each ink the absolute values printed by the press for each percent of ink (Tone Value). The G7® Gray Balance curves shows the weighted Delta Chroma of the CMY combination of the Gray Balance patches, the a* and the b*.

The Table gives the L*, a* and b* values of your profile, the reference profile and the difference in ∆E (2000), ∆C and ∆h. The primaries, substrate, black point and volume of the gamut can be used as a means of comparison. If there is enough G7® information, the weighted delta L* for CMY and K and the weighted delta Chroma* for K will be shown in a small table bellow the rest.

3. Profile settings

The different settings that can be managed are the following:

• Profile name
• Process type
• Color separation
• Profile tables

The Profile name allows to personalized the name of the profile (both the internal and the external name).

The Process type optimize the combination of inks measured for the printing process technology used. The "Other" option corresponds to the default technology used when the press is not specified.

The Color separation has different parameters depending on the Black Generation selected.

In CMYK there are 2 separations:

• General Purpose GCR: CMYK values are calculated with a Heavy GCR (1.7), Kstart at 10% and a Kmax at 98%. Only the TAC can be modify.
• GCR stands for Gray Component Replacement i.e. Black replacing CMY grays in the separation. The following parameters can be modified:
  • TAC (%) Total Area Coverage indicates the maximum amount of CMYK overprint obtained in the Output separation.
  • K Start (%) indicates where black generation starts. Black ink component will be generated for colors having a L* lower than [100 – K Start].
  • K Max (%) indicates the maximum desired amount of Black that can be used.
  • GCR Level menu allows you to choose the strength of Black replacement. The range of selection is very wide, from No Black (CMY only) to Maximum Black replacement (practically all equal amounts of CMY are replaced by equivalent black). GCR levels with a * correspond to Adobe Photoshop® default GCR levels.

In HiFi there are also 2 separations:

• Minimum TAC and Ink Usage: This option allows you to use the minimum amount of total ink possible to reproduce colors, resulting in significant Ink Savings. The following parameters can be modified:
  • K Start (%) and K Max (%) are similar to GCR Separation, see previous paragraph description for further details.
  • TAC (%) Total Area Coverage indicates the maximum amount of ink overprint obtained in the Output separation. If dark colors can be reproduced with a lower amount of ink, the TAC separation will be lower than the chosen value.
• Priority to CMYK Inks: This option allows you to make a HiFi separation which gives the priority to CMYK inks usage over other inks, and for CMYK inks it will give the priority to K ink usage over CMY inks. K Start (%), K Max (%) and TAC (%) parameters are similar to GCR Separation, see previous paragraph description for further details.

The Profile tables section add some modifiers when creating the tables of the profile. The table size is the number of steps the table is divided by; the bigger the tables, the bigger in weight the profile will be (especially for HiFi).

The button Build Profile will start to create a profile with chosen data, settings and the profile name. Once created, you can come back to this step to check the settings. The button will change its name to View Profile as it won't re-create a profile already created with the exact same parameters.

4. Profile viewer

This step allows you to compare the ICC Profile created with a Reference profile by showing their 3D Gamut and some numerical values.

The Reference profile list can be used to compare your profile with one of the profile in our database. It should contains most of the standard profiles used in the industry.

All the information about the profile can be found in the following tabs:

Gamut

The Gamut viewer has multiple functions:

• Display the 3D gamut or the 2D gamut (in 2D mode all the other functions are disabled).
• Show the gamut from the top or from the bottom thanks to the arrows.
• The Slice slider will remove a part of the gamut, starting from to top at 100 and finishing at the bottom at 0, keeping only the primaries.
• The 3 gamut buttons allow to show the gamut (whether your profile or the reference) in 3 different ways; from left to right: - full smooth gamut, - triangles depending on the table size and full gamut, or - only the edge of the triangles.
• The Opacity slider modifies the aspect of the gamut to be able to see through it. This is useful when comparing it with a reference profile to be able to see what is inside and what is outside.

Colorimetric TVI

TVI stands for Tone Value Increase. The curves show for each percent of ink (Tone Value), what is the increase (or decrease if negative) of ink provided by the profile. The thick lines correspond to a smooth curve while the thin lines are the reality of the percent measured.

Colorimetric TRC

TCR stands for Tone Reproduction Curve. It is the equivalent of the TVI but rather than showing the increase it shows the absolute values printed by the press for each percent.

G7® Gray Balance

The G7® Gray Balance curves correspond to the weighted Delta Chroma of the CMY combination of the Gray Balance patches, the a* and the b*. To check if the profile is close to neutral in the gray, check if the curves are close to 0 for each percent of ink.

Table

The table gives the L*, a* and b* values of your profile, the reference profile and the difference in ∆E (2000), ∆C and ∆h. The primaries, substrate, black point and volume of the gamut can be used as a means of comparison. If there is enough G7® information, the weighted delta L* for CMY and K and the weighted delta Chroma* for K will be shown in a small table bellow the rest.

Measurement Module

This tool contains all the information needed to measure correctly your charts.

0. Interfacing with the computer

The first time trying to use the Measurement Module displays instructions to install the Alwan Endpoint allowing to interface the instrument connected to your computer with the Measurement Module on the website. After downloading the software, you have to install it on the computer and allow the website to call it.

• On macOS: for some user the application is recognized as "from an unidentified developer". If it happens, you need to go in System Preferences -> Security & Privacy, click on the lock to make changes and then on "Open anyway". Finally, the first window will show again with the option to "Open".

Once installed, the browser asks to allow this site to open the alwan+endpoint link with Alwan Endpoint. Check "Always allow https://colorcloud.alwancolor.com to open alwan+endpoint links" to have a working connection.

1. Connection

If you don't see the list of all the instrument, please check "Interfacing with the computer" first. All the instrument that we support are available in the carrousel which rotates using the arrow on the left and right of the instruments displayed. The instrument needs to be on and linked to the computer. Bluetooth is not supported, the connexion needs to be via cable.

Techkon instruments are only supported on Windows.

2. Configuration

Mode

The Measurement Mode, as defined by ISO 13655, can be selected depending on the instrument used:

• M0: illuminant A - UV not controlled
• M1: Simulate illuminant D50 - with UV conform to standard
• M2: Simulate any illuminant - without UV
• M3: Simulate any illuminant - with polarization filter

M0 is the most frequent mode used in today production. M1 is selected by default.

Illuminant

Standard illuminant can be computed depending on the parameter selected.

Observer

The instrument observer can be 2° (by default) or 10°. The 2° Observer refers to CIE 1931 standard colorimetric observer model. It will be used for colorimetric computation of CIELab tristimulus values.

Density Status

Density will be computed according to the Density Status thanks to the spectral values in the measurement file. Status E is commonly used in Europe while Status T is commonly used in America.

White Base

White Base can be Paper (by default) or Absolute. If Paper is selected, Density will only take into account the ink density (zero density is paper). If Absolute is selected, Density will take into account paper and ink density.

Backing

It depends on the backing of the measurement used. By default the White backing is selected. Some instrument also supports the Black backing.

3. Chart selection

In this step you can select one of the Alwan charts or import your own chart. Depending on your needs, you can download the following packages to print the chart to use:

• for profiling: download the Hydra Charts Package
• for calibration: download the Calibration Charts Package
• for assessment: download the Process Control Package

When importing charts, please respect the CGATS formats for the order of the patches to be correct and measurable. Multiple page charts can't be used.

4. Measurement

Settings

This tab concentrates all the settings to manage your device: the patch length, the patch weight (depending on the instrument) and the mode of measurement (patch mode or scan mode). The Disconnect button will put you back to the selection of the instrument. The Calibration button is mandatory for most instrument when starting to measure. It can also be asked to click it after multiple measurements or a long time without any measurement done.

Chart

This field contain the information about the chart to measure and the results of such measurement once it is done. Also, the chart at the top of the window will show the top part of each patch as the reference color and the bottom part as the color measured. Below it, the Graph tab will show the curves of the measurement done and the Table tab will show the numeric values.

Info

This tab shows all the steps to take in order to measure correctly. Any error of manipulation or device will also appear in this zone. The three available buttons are:

• Revert: for manual instruments it helps to go back one patch or one line (depending on the mode) to measure it again. For automatic instruments, it will help to re-triangulate before doing the measurement.
• Stop: to stop the device in the middle of a measurement. Some automatic instruments may have to finish the line they are measuring before being able to stop.
• Measure: to start the measurement.

Measurement list

This field contains all of the measurement done. Clicking on one of them will select it and show a representation of the patches, the graph curves of what was measured and the table of the numeric values. It is possible to remove it with the Clear button.