- The control with LithoScan Professional/ LithoScan 2D/ LithoScan Basic/ LithoScan Flash is faster, more accurate and reproducible as the printer's manual control. Even if the printer is using a manual operations.
- Monitoring of dot gain(1) and trapping(1) as well. These information can be forwarded to the pre-press department to enhance the quality
- Separate 2D measuring and control system
- Desitometrical and spectral readings
- Dynamic Control
- Dot Gain & Trapping(1)
- Job Quality Report
- Process Standard Offset (PSO) /G7 Reports
- Spectral reference values from own color database or from samples
- Control of the single colors only by measurement of combined printing.
- Compensation of trapping and dot gain
- No need for color bars under certain circumstances
Optimized colorbars for all LithoScan systems are free downloadable at the Lithec website Lithec.de
Positioning: If the colorbar is disrupt – for example to place cutting or folding marks – the following part must begin with the element which follows the last element of the previous part
According to ISO 12647 , measurments need to be normed on a different paper group
According to ISO 2846-2:
L=95 (+/-2) a=0.0 (+/-1) b=-2 (+/-2)
Maximum tolerance = deltaE 5
Keep in mind that a printing press naturally varies, and a typical tight tolerance for density
is ± .05 D.
A good demonstration of the normal variation of the press is to measure the same patch on ten press sheets, pulled at one-minute intervals, then record and plot the density values.
This shows how density varies with no adjustments to the press.
Status T / ANSI T: wide band color reflection densitometer response, used mainly in United States
Status E / DIN: wide band color reflection densitometer response, used mainly in Europe, main difference to Status T: higher values for yellow
Status A / ANSI A: wide band color reflection and transmission densitometer response, used mainly in the photographic industry (measurements of prints and slides)
Status M: wide band color transmission densitometer response, used in the photographic industry (measurements of negatives)
Status I / SPI, DIN NB: narrow band densitometer responses, rarely used
Status G: "traditional X-Rite graphic arts response", was used about ten years ago mainly in USA in X-Rite's 400-Series, today only a "compatiblity-feature" of newer X-Rite densitometers
Status Ax, Ex, Tx:: Old, classic densitometers use filters made out of glass or gelatine (some Gretag or X-Rite instruments). The new generations of densitometers are spectrally based. This means, that modern devices measure a spectral curve and use exact mathematical filters to calculate the density. Contradictory to this the responses of classic densitometers have slight deviations compared to the responses defined by ANSI/DIN/ISO, because the accuracy in manufacturing glass or gelatine filters is limited.
HIFI: Status E responses for CMYK, additional filters for red, green, blue and orange)
What is Delta E?If difference is a number showing how 'far apart' two colors are, tolerance is the meaning of the number. Setting a tolerance level (such as 2.0 dE76) defines what you will accept and what you will reject(reproduction tolerance).
- for basic / fast calculations, you can use dE76 but beware of its problems
- for graphics arts use we recommend dE94 and perhaps dE-CMC 2:1
- for textiles use dE-CMC
DeltaE Calculation /General:
dE calculations are based on colorimetry which means they are illuminant-dependent. Don't try comparing numbers calculated from colors viewed / measured under different illuminants.
differing dE due to illuminant is metamerism. If colors are 'adapted' to the same white point then you have a metamerism index.
DeltaE Calculation /CMC:
In 1984 the CMC (Colour Measurement Committee of the Society of Dyes and Colourists of Great Britain) developed and adopted an equation based on LCH numbers. Intended for the textiles industry, CMC l:c allows the setting of lightness (l) and chroma (c) factors. As the eye is more sensitive to chroma, the default ratio for l:c is 2:1 allowing for 2x the difference in lightness than chroma (numbers).
There is also a 'commercial factor' (cf) which allows an overall varying of the size of the tolerance region according to accuracy requirements. A cf=1.0 means that a delta-E CMC value <1.0 is acceptable