Step 2: Printing step wedges

From the PrintStepWedges folder, select the relevant Step Wedge file to print.  If you are printing to a sublimation printer (transfer paper) you will need to print everything flipped.  There are flipped spool files in the folder for your convenience.

Print the correct file, relating to where the black head is.  The files are laid out this way so that you can strip read the step wedges.  To be able to strip read them, the black has to be in the right place, otherwise the guide lines may print cyan, magenta etc and strip reading will not work.

The printed Step Wedges will look similar to this:

The reason we print the step wedges 3 times is because having 3 readings of each head averages out the readings and interlacing on the heads, making for a more accurate measurement.

Step 3: Reading stepwedges in

From the ReadStepsIn folder, open the file which relates to the number of inks you have in the printer into PrinterCal.  In the snapshots above, there are 8 inks, therefore I would open the Triple 8 steps.

When these are opened into PrinterCal, they look like this;

The colours used in the Printer Cal file will not match those printed.  Do not worry about this.  It may also look as if there is only one set chips.  Do not worry about this either. Much like reading a profile in, PrinterCal will automatically move onto the second page when you read in the last line of page one.

It is important to read the chips in in the order they printed.  Do not follow the ink order of the PrinterCal file.  Therefore, starting at the top, read each line in from top to bottom.

As with reading in a profile, a graph window will open when you have completed the reading.  The graph will look similar this this:

Save the measurements.  It is recommended you put the printer name, substrate and ink type into the filename.

HPNonWovenLatexSteps is a good example of a file name.

Step 4: Printing an ink loading test sheet 

The Ink Loading Test sheet print will help determine what the maximum level of ink the substrate can take without bleeding / distorting or saturating.

The print will contain combinations of 2 colour corner (RGB mixes) as well as 3 and 4 colour mixes, to determine darker mix limits.

It also includes a 2002 target (target at the foot of the sheet) should you wish to create a Custom Overprint for the digital printer.  This can then be used to improve gamut simulation when creating an ink setting for said printer. The 2002 target should be read in via the standard 2002 target format in PrinterCal then measurements forwarded to Support for Custom Overprint generation.

This process will require a spool file to be produced from an AVA4 file. Ensure you open the file downloaded below on a design or colouring station. This process requires the ability to spot print, if you do not have this feature please contact AVA Technical Support for assistance. 

1. Open the downloaded file ‘InkLoadingtest.ava3’ into AVA. The file is located in the ‘InkSettingFiles3_2015’ folder downloaded earlier.
2. Arrange the layers according to your Head Test print.
3. The first 4 layers must be recoloured using the Custom Overprint Picker.  So, Alt click on the first layer and adjust the slider for the first colour to 100.
   
   

The main aim here is to get the CMYK information layers in the correct position.  Any other inks are just represented positionally by the blank layers. Head 1 colour should be at the top. The example below shows an initial head test strip print with CYMK the first 4 layers with the ink loading test file layer order re-adjusted to match.

4. The file itself is around 620mm wide, however should you wish to print the file at a specific width, the download includes some pre-made layout window templates for various widths.
   
5. Go to AVA Menu > Settings > Printer and make sure only Spot Printing Layers is ticked under Printing Mode;
   
6. Then, in your Layers Palette, click on the printer icon beside all of the layers.
   

7. Go to File Menu > Page Set up. Click Set from Document and set the correct resolution. Ensure that you tick flip horizontal if you are printing for a transfer process.
8. Go to File Menu > Print.
9. If you are already networked and sharing the Print Queue save the spool file directly to it OR you can save it to the desktop of the design station. The spool file can be transferred and copied into the Print Queue via USB stick if necessary.
10. Go to the Print Queue window in the AVA Digital Print Rip application. Ensure that the ink setting is set to Step Wedges by checking in the bottom left of the queue window.
    
11. If it isn’t, in the button options at the top of the queue window, click Colour Separation > Ink Setting list > Step Wedges. Click OK to set.
    
12. Select the Ink Loading Test spool file from the queue list and click print in the top menu bar.
    
13. Put the print through the relevant finishing processes so it can be assessed appropriately later on in the process.

Step 5: Building the ink setting

Once the step wedges are read in, you are ready to proceed with making an ink setting! Firstly, ensure you have a copy of the latest InkSetting software.  

Launch the InkSettings application and open your step wedges using File > Open.

Four windows will open as you do this; Channels, Colour Wheel, Grey Ramp, InkSetting Simulation.

Open your Step Wedges

1. In the InkSettings software, go to File > Open, and  open the step wedges you read into PrinterCal.
2. In the Channels window, name each of the channels, and change the Role for each one.  The Role for blacks and greys should be changed to Grey.  The Role for cyan, magenta and yellow (and blues, oranges, reds and greens if you have them) should be set to Chromatic.
   

Setting your input limits

Input Pair Limit – this is the maximum amount of ink per head which will be put down onto the substrate.  The default is 75% which in many cases may be too little, resulting in a reduced gamut.

What should the input limit be?

Using the Printer Cal measurements from the step wedges, the physical printout of the step wedges and the Density and Chroma details in the Channels window, you should be able to determine this.

Density for Black Ink (K)

By determining the level of density at which the black stabilises, you will in turn be determining the input limit where the colour stops benefitting from more ink being laid down.

The slider bar along the bottom of the Channels window adjusts the Input Level, Density and Chroma values.

To get the most out of your printer, you need to find the point at which the density value of the black stabilises.

Keeping a close eye on the density reading of the black, begin to move the slider bar to find the point at which the reading stabilises at one decimal place (so if the 3rd decimal place increases, this is tiny increments so the limit would, i.e.. 1.2 > 1.22)

Chromaticity for Dark Colour Inks (CMYOBRG)

Chromatic is an objective specification of the quality of a colour. It is made up of two independent parameters; hue (h) and saturation (s), otherwise known as chroma or intensity.

By determining the level of Chroma at which the colour stabilises, you will in turn be determining the input limit which the colour benefits no more further ink lay down.

Input limiting using Chroma values is applicable only for colour dark inks such as Cyan, Magenta, Yellow, Orange, Blue, Red and Green.

The slider bar along the bottom of the Channels window adjusts the Input Level, Density and Chroma values. To get the most out of your printer, you need to find the point at which the chroma value of your colour stabilises or even drops.

Keeping a close eye on the Chroma readings, begin to move the slider bar to find the highest level of Chroma.

Repeat this process for each dark colour ink in the printer.

Step 6: Add your separations

Adding the inks as a ‘separation’ to the ColourWheel window

In the ColourWheel window, click the Add Separation button on the left hand side of the window. This will add a dot in the wheel.

Slide this dot around the the appropriate place on the wheel.  For example, if this is to be the Cyan separation, slide it around to the cyan section of the wheel;

Click the Edit button towards the middle of the window.  A sheet will open.  Tick the Cyan box, and if you have a light cyan, tick this as well.

Repeat steps 1 – 3 for each ink except Black and Grey.

Add the black, and grey if there is one

In the Grey Ramp window, click the Edit button towards the middle of the window.  A sheet will open. Tick the Black box, and if you have a grey, tick this as well. The InkSetting Simulation window will now show you a simulated gamut.

The InkSetting Simulation window will now show you a simulated gamut.

Add light inks

You should start this process by finding out at what point the light ink stabilise. By this we mean at what point does the density of the readings start to decrease? We will use Cyan and Light Cyan for this example.

1. Open the step wedges into ColourSys.
2. Drag the Cyan readings into a new colour file.
3. Drag the Light Cyan readings into a new colour file.
4. Go to Colour Menu > Dot Area.
5. From the Cyan readings, drag the 0% chip into the top box, and the 100% chip into the middle box.
6. Change the value in the bottom right hand corner to 100, and click Document and save the file.
7. Click on the colour file containing the Light Cyan readings, and repeat steps 5 and 6.
8. Open the two saved documents.
   
9. In the light ink, look for where the tones start to fluctuate. In the example above, this would be 0.968 (96.8%), because after that, the density then drops.
10. Now look in the dark inks, and try to find a value as close to this as possible. From the example above, this would be either 0.960 or 0.973, depending on whether you wish to round up or down.
11. This tells us we can use the light ink up to 96%. Because the light inks are stable up until 96%, you would not need to use the dark in the low tones, and can start to introduce theses much later in the mix (which will avoid dither).
12. You need to drop the light tones out of the mix before they hit the maximum tone at which they are stable, otherwise you may get undesirable banding in printed gradients. The above inks are considerably stable compared to some you may come across. Achieving a nice strong mix without the substrate becoming over saturated will be your aim here. A suggested ink mix for the light and dark cyan inks for this example may look a little like this:
    
13. Ultimately, you need to get that grey line as straight as possible.

Analysing and controlling ink loading within the ink setting

Ink loading refers to the total amount of ink that the substrate will handle at any given time, without causing issue to the said substrate. It is important that ink loading is controlled carefully to reduce such issues and ensure as much accuracy as possible in the final profile. Dependant on the type of printing and substrate, such issues could include:

• Bleeding or pooling of ink: a generic trait for many processes
• Ink coming through to the back of the substrate: direct to fabric, reactive, acid
• Cockling / rippling: pigment, thinner substrates such as vinyl, wall coverings
• Unsuccessful fixing processes: transfer sublimation – too much ink left on the paper after transferring / reactive or acid process – bleeding ink after steaming or washing / pigment – ink rubbing off after heat treatment.

For this section, you will need to examine the ‘Ink Loading test’ print you did.

Analysing the ink loading test sheet

Analysing of the Ink Loading test sheet can be done both visually and numerically. It goes some way to knowing exactly how much ink one can get away with  putting down on the substrate without causing issues when mixing colour from the various ink heads. The test sheet consists of blocks of 2, 3 and 4 colour CMYK ink mixes.

Analysing of the Ink Loading test sheet can be done both visually and numerically. It goes some way to knowing exactly how much ink one can get away with  putting down on the substrate without causing issues when mixing colour from the various ink heads. The test sheet consists of blocks of 2, 3 and 4 colour CMYK ink mixes.

Visual analysis

Take a good look at all the areas on the test sheet and you will see percentage amounts for the ink loadings of that particular block displayed around it. Just like single channel limiting, it is not always the most dense looking mix which is appropriate to go for, so visual analysis can be misleading, however when used with the Chroma method from the Channels window, a compromise can be found where the best combination of ink use and saturation is achieved.

Look for any bleeding or pooling of ink on the blocks. Look for where the fine line details in the larger 2 and 3 colour blocks begin to get filled in. Look for any ghosting of the flat edges of the blocks begins to appear. Is the ink coming through the substrate if the substrate is fabric, or is it leaving too much ink behind on the paper if you are using sublimation inks. Pay close attention to the strips of black across the larger 3 colour blocks also if you are looking to mix a CMYK black.

Be sure to mark or ring the blocks you choose with a pen so as not to forget when adjusting in the ink setting. An example is shown below showing the areas marked before the colours begin to blur and bleed:

 Chroma RGB analysis

A set of 2 and 3 colour head mixes are included in the top right of the test sheet for chroma analysis in the ink setting application. Simply use a 4 colour step wedge file from here and read the red, green, blue and dark mix strips into PrinterCal exactly the same as you would the standard step wedges. Once read in, load the step wedges into a new ink setting project and go straight to the channel window. From here, the input level slider and chroma readings can be used to find the maximum chroma of the ink mixes. As the level is increased, chroma may become unstable or start to drop. The level should be set shortly before this point. This will give the user a clear indication of where the 2 and 3 colour mixes benefit from no further ink letdown.

Controlling ink loading in the ink setting

There are 2 sections within the Colour Wheel window of the ink setting project where ink loading can be controlled. Ink Limit and Boost do not denote the ink load amounts, just follow the instructions below to set them up, then use the Explore RGB window to find out exactly what ink loading is detected at certain points of the simulated gamut. The Ink Limit and Boost can then be altered according to both the read out of the Explore RGB window and the findings on the printed Ink Loading Test sheet.

Ink Limit

This slider controls the total ink limit created in the most saturated RGB corner mixes of the profile simulation. An entry of 2 would represent 200% ink load, 100% of each of the ink used, based on its single channel limited values. Try not increase the value past the point where the colour chips in the simulation window begin to fall on one another. In the example below, the ink limit is reduced eventually to around 1.7 (170%), the point where the dots in the simulation reach their final point and begin to pile up on top of each other.

Boost

Boost represents the addition of the specified black mix in the main bulk of the profile. Since this is where the darkest colours are mixed, it is generally where the heaviest ink loads will occur. Spin the gamut simulation around to view the dark end of the profile. Now increase the boost until the dots stop pushing down or just before. The final decimal number will denote a maximum ink loading within the gamut. So, for example, 1.2 would denote 120% maximum ink loading. It maybe that the figure obtained from the analysis of the Ink Loading Test sheet is more, however maximum ink load within the gamut will only ever be based on a combination of single channel output.

Explore RGB - Checking your final ink loadings

The Explore RGB gives the facility to explore the spectrum of colours created by a gamut and find out what possible ink loading will be used in certain areas of the profile. It can be opened via the Explore RGB button on the Simulation Window. Whilst the window has various picker types, we recommend that HSL slider second option is used.

By sliding the saturation and lightness sliders all the way to the right to 100%, we can begin to explore the most saturated corners of the mixes, red, green, blue, cyan, magenta and yellow. Now enter 0 in the hue amount box. This starts the analysis off in the red corner of the gamut. In the example below, the ink loading is at 70%, as this ink setting uses a red ink for that corner. By entering then 60 into the hue amount, focus skips to Yellow, 120 to green, 180 to Cyan and so on. This gives us the chance to see if any of the corners exceed the maximum ink load as determined by the 2 colour mixes on the ink loading test sheet print analysis. If ink loading is over what was determined, the ‘Ink Limit’ slider should be reduced, and another check done in the ‘Explore RGB’ window until the loading limit is reached.

From this point, of the darker colour mixes, simply reduce the lightness slider down. You will notice that the ink loading will increase as colours get darker, as it uses more head mixes. Find the maximum ink loading. If it is too high, then reduce the ‘Boost’ slider and recheck the Explore RGB once more, until the predetermined loading limit for 3 colour mix in reached. For those of you mixing a special black CMYK mix, please bear in mind that this mix may need to be adjust in the Grey Ramp Window, should it exceed the loading limit.

Test Printing

The importance of testing an ink setting

If you do not test an ink setting, how do you know if it’s any good? It is a time consuming but vital process because it will determine whether the inks are mixing well. If you have mixed a black using Cyan and Magenta inks, then you will need to make sure that any grayscale’s the customer prints are in fact grey, and do not break down too blue or too pink. This is the downside to mixing special blacks.  Most customers want a nice neutral grey, which is incredibly hard to mix. And therefore testing is vital.  But this involves a little more than just printing a design.

Step 1: Profile the ink setting

If you have made several versions of your ink setting you should profile all of them. This is the time consuming bit, especially if you have to steam and wash the targets, but again – it’s a vital process.  Once you have printed all of your targets (one for each ink setting), read them in and ensure you are happy with the graphs.

Doing some test prints

If you are working with reactive inks, which need to be steamed and washed, I highly recommend making several variations of an ink setting at one time so that you can bulk read the profiles, and print several test prints at once (please remember to switch the profile and ink setting between prints) because it can take 3 to 4 hours to get your prints back.

You should gather a range of designs and colourways to print as a test.

It is important to print lots of designs and colourways of these designs as it will enable you to truly evaluate all colours, particularly beiges greens, navy and greys.

To test the black, create a file with one 8 bit layer in to, and draw a linear vignette across it, ensuring you have 100% and 0% in the file (i.e. do not start and finish your vignette outside of the design).  This file should probably be around 1 metre square.

Print and finish (either bake or stay and wash depending on the inks you are working with) the designs and check the colour match with a diff test if necessary