ITL Image Grader

The ITL Image Grader provides an easy-to-understand appraisal of press and print quality that can be used by businesses of all sizes. It assesses the acceptability of print system image quality by analyzing pages printed under normal press conditions; extracting and grading image attributes; and combining the grades into color, solids, and line/text attributes and then into an overall grade. The customer prints from a PDF file provided by ITL using existing press settings, paper, and ink/toner. After analyzing the printing, ITL delivers a set of reports that assigns a letter grade to various aspects of image quality and also shows the customer how his or her press compares with others in terms of print quality and lets them know where they stand.

In general, the ITL Image Grader evaluates results of the entire print workflow, not individual process parameters—the "what" of image quality, not the "how." The scores are independent of the printing process and the size and/or speed of the press and have been exercised all the way from desktop printers to large offset presses and wide-format printing units. The ITL Image Grader can grade any equipment that can print a PDF. The reports are authoritative, extremely easy to understand, and do not require technical knowledge—they are as easy to read as a school report card. Special ITL Image Grader applications can also be used to compare performance before and after service or when equipment is moved to look at press history over time or under different settings or to compare several presses at the time of a planned business transaction.

Description:

The ITL Image Grader assesses the acceptability of print system image quality by printing a set of PDF pages under normal press conditions, extracting and grading about two dozen image attributes and combining the grades into color, solids and line/text attributes and then into an overall grade.

In general, the ITL Image Grader evaluates results of the entire print workflow, not individual process parameters – the “what” of image quality, not the “how” – from PDF to paper to observer. The scores are independent of the printing process, the size and or speed of the press and have been exercised all the way from desktop printers to large offset presses and wide format printing units. The image quality acceptability of a print depends on the print system, the image content and the personal preferences of the observer. Acceptability also depends on how the observer balances the conflicting assessments of different parts of the image and aspects of the rendering. To obtain an objective assessment of the print system alone, the ITL Image Grader first dissects image quality acceptability into “attributes”: two dozen pseudo-independent measures of contributors to quality, independently assessed from features in the image set. Then these scores are hierarchically combined into major attributes. Finally, the ITL Image Grader assigns category and overall grades based on the importance of the attribute, using a patent-pending process that mimics customer perception giving greater import to a low score than to higher scores in related attributes. The grades measure the acceptability of the image quality; they are not process metrics (such as microns, delta E, etc.) that are more suitable for process controls. The grades are even-handed, comparing presses using different print technologies. The ITL Image Grader can be said to measure the success of process controls and how well the press system delivers its potential in the prints.

Results:

The Image Grader results are presented to the customer as a three sheet PDF. The first is an academic-style report card. The remaining sheets offer analysis and insight, positioning major grades against histograms of the grades awarded to similar presses and against all ITL scores. Attributes of particular strength or weakness are also identified.Special reports are also available that present before/after or head-to-head comparisons in sharper detail, looking at press history over time or under different settings or comparing several presses.

View a Sample Image Grader Report

Grading Principles:

Color is defined technically by three scientific components – the Color (Hue), the Saturation (Chroma) and the Lightness, all of which can be measured by instruments. Unfortunately, the human eye sees color in quite a different way. The eye can tolerate different levels of color mismatch, depending on the color viewed. For example, the eye is very sensitive to slight changes in blue but can tolerate much larger changes in yellow. The ITL Image Grader grades color in the same way as the customer, namely, by primarily using our eyes, complemented with instrument readings. As with its color grading, ITL grades a press based on the acceptability of its prints to customers using a methodology combining instrument measurement with visual assessment. This not a simple "how much do you like this print?" - A, B or C. There are so many variables and so much subjectivity in a single point assessment that such scoring would not be repeatable and, more importantly, would not point to corrective actions for the print system. As with its color grading, ITL grades a press based on the acceptability of its prints to customers using a methodology combining instrument measurement with visual assessment. This not a simple "how much do you like this print?" - A, B or C. There are so many variables and so much subjectivity in a single point assessment that such scoring would not be repeatable and, more importantly, would not point to corrective actions for the print system. After grading, the attribute scores are rolled up into three category scores: Color, Solids and Lines & Text. The Category scores are rolled up into an overall grade for the press. In some categories, the print builds up points by doing good things, but in more cases, the print accumulates demerits because the customer expects no streaks, smooth solids, real blue skies and neutral neutrals. Thus, some "roll ups" are weighted averages of the attribute grades while others use an adaptive algorithm which penalizes low scores more than it rewards high scores, mimicking our own perceptions of print image quality. ITL grading is independent of the printing process. Ink jet, electrophotographic, offset and other print technologies exhibit very different micro-structures and must conquer different technical challenges, but a customer's eye steps back and looks at the big picture, not the micro-structure or how the technical challenges were contained. The attribute grading mimics the human eye, and in most cases is a real human eye, in how it looks at images.ITL attributes and grading avoid specific preferences like gloss, texture and gamut, which are application specific and under the printer's control with ink and paper selection and post treatment.

 ♦Works on all digital web fed presses. Both liquid and dry toner. This grading service and set of drop-and-play PDF targets assesses and grades your toner web fed equipment.

♦The attribute model and the specific attributes (eleven attributes shown on the report card plus about a dozen sub-attributes).

♦Methods to score each attribute without bias to any particular print technology.

♦A method of combining attribute scores that gives appropriate weight to and mirrors the way a customer builds an overall assessment from disparate image features.

♦A simple, understandable way to communicate the fifteen grades from an image and the overall simplicity of running our process.

♦The ITL Image Grader provides an affordable, industry-wide and independent grade that compares the actual image quality of different printing devices. This serves as a mirror for the industry and a new way to improve print management.

♦The ITL Image Grader benefits commerce because it brings the users of printing equipment a new way to communicate with vendors. It brings printing operations a new way to communicate with customers.

♦ITL Image Grader is an economical and proactive tool that helps predict how customers will accept a printed image. The ITL Image Grader provides management with something new: a clear definition of what is expected as measured by an independent third party.

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Published on Wednesday, August 27, 2014 (updated 09/02/2014)