Textile and dye-sub printing and profiling, general considerations

Textile and dye-sub add additional variables to the printing and profiling process, which is why you need to take several things into account.

General considerations

• Textile profiles can take 4 or more hours to create, in some cases days.
• Changes in the environment need to be considered;
  • Relative humidity should be controlled, per printer or printhead specifications.
  • Generally, humidity should not be below 50%.
  • Often, patches for a single profile should be printed and read over a series of days
    to account for these changes.
• Consider material stretch, this can affect the consistency of readings;
  • Read and average multiple readings.
  • Use a device with an electrostatic base.
  • If the Caldera TotalColor is being used, print the 8mm patches then read in 6mm.
  • Press temperature, pressure, and dwell need to be considered in the profiling process. Note these variables when profiling.
  • Understand temperatures across the web of the press and avoid outliers such as hot spots or colder areas. You can use an infrared thermometer to measure.
  • Weave, texture, gloss, and stretch add noise and inconsistency which a narrow aperture may not account for.
• A larger aperture such as 6mm or 8mm is necessary for many textiles;
  • The wider aperture accounts for the weave and texture.
  • An 8mm, although wider, may not be optimal. Testing may be necessary to find the
    optimal size for the application.
  • The Caldera TotalColor supports 6mm and 8mm.
  • The Caldera ColorPad has a 6mm aperture.
  • The i1 Pro 2 has a 4.5mm aperture, so multiple readings are suggested to help offset the
    smaller aperture size.

Technical recommendations

• Illuminant D65 (standard daylight) for the 10-degree observer, is the standard for the textile industry.
• Generally, 3 or more patches should be printed, then read and averaged. 
• Always test gradients with raster files such as a TIFF in addition to PDF files with vectors.
• For custom spot color mapping use PDF format, as older file formats like EPS and PS have limitations
• The UV cut filter is not necessary for textiles with OBA (Optical Brightening Agents).
• The polarization filter available for the Caldera TotalColor may be necessary for polyesters with
  a high degree of gloss.
• In the event proofing is done against a textile profile on a proofing printer, make sure proofing
  paper has a similar amount of OBA as the textile.
• Spot colors with gradients can result in poor results, a composite RGB can be used instead.

Useful instruments

• A spectrophotometer, such as the Caldera TotalColor.
• Static sample holder.
• UV flashlight (blue light) to identify OBA.
• Infrared thermometer to verify press temperatures.
• A magnifier or loupe.
• A light indicator for D50 and D65. Some Pantone books contain these indicators, as does the box in which CalderaRIP is shipped (for hardware license customers).
• Pantone swatch book (the solid-coated book accounts for OBA).
• (Optional) Portable light box.

RGBWorkflow recommendations

When profiling for RGB, please consider the following about the separation methods:

Black Only method:

• Recommended when the printer has a good strong black.
• Also when light black inks are used to avoid dithering (hard dots causing graininess) in the light black areas (quarter tones).
• Generally don’t use this option with a CMYK-only inkset.
• Use this option to help reduce metameric effects to the minimum.
• Minimizes process variations (e.g. reactive printing).
• Helps with ink savings.

Black Mixing method:

• Recommended if a combination of inks is better than pure black only and if the printer has light
  black(s). Also, when a gray ink is present and the black is not optimal.
• Use this option to produce neutral grays, noting graininess could occur if there is
  no light black ink.
• The black chart should be printed to select the best black.

GCR  method (general default):

• Use it if a combination of ink is better than pure black only but no light black is
  present.
• The light areas of black will be replaced with CMY inks to minimize dithering and
  graininess.
• Cyan Magenta and Yellow do not always have the same light fastness and can fade over time at different rates, resulting in non-neutral output over time (outdoor flags and banners).
• Obtaining a neutral gray can be more challenging, so ensuring proper ink restrictions
  and linearization curves are built beforehand.
• The black ink can or can not be optimal.
• The black chart should be printed to select the best black.

No Black method:

• Generally, used when no black is present.
• Potentially a good choice for ceramics.
• If profiling for RGB use 11.1 or higher which includes the option for smoothing in the ICC build
  options.

When evaluating RGB black swatches, evaluate the patches outside or in a controlled lighting
environment.

RGB profiles can result in graying out of gradients, especially with PDF files. If that's the case, then consider the following:

• Properly identify if an RGB file is the best option for their application beforehand.
• Profile in CMYK with a heavy GCR if RGB profiling is not appropriate.
• In the case of RGB or CMYK output profiles, simulating sRGB effectively simulates
  flattening to achieve better gradations.