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REVIEW:

Colortrac SmartLF Ci 40 large format scanner

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Accuracy

The utility software supplied with the Ci 40 includes two main calibration options - normalisation and auto stitch.

Colortrac suggest that users perform normalisation regularly, but that auto stitch only needs to be used if discontinuity problems (e.g. breaks or steps) occur in your scans. Both procedures are very simple to run. They involve scanning a supplied target and take about two minutes each.

The targets are supplied in a long paper envelope which is not protective enough. Even the new targets supplied with the production scanner had slight crumple marks on them and the normalisation target had a damaged corner. We recommend that Colortrac supply its targets in sturdier packaging.

We scanned an A0 (E size) drawing in portrait. We measured the lengths of the lines on the drawing and compared them to the lengths of the scanned lines. Across the scan, accuracy was just within tolerance on the pre-production model we reviewed and just outside on the production model.

We found a 5 mm / 0.2" error along the length of the scan in the pre-production model and a 16 mm / 0.6" (!) error in the production model. We were able to correct these errors using the Motor Speed option in the Ci 40 Utility Program but this required some calculation on our part.

Users should not be expected to have to do this immediately on purchasing a new scanner. Colortrac state that the issue was due to the motor speed being incorrectly set in the factory. They say that they have put quality checks in place to prevent it from occurring again.

Resolution

We scanned a standard T-10 resolution chart (see our large format scanner resolution article).

Five cycles per mm is the smallest test element on the T-10 chart where we are just about able to resolve individual lines by eye. Lines closer together than this cannot be resolved by the human eye and so are unlikely to be found on a CAD drawing.

Below is the 5 cycle per mm test element scanned by the Ci 40, displayed at 1 pixel on the scan = 1 pixel on the screen size.

The lines are easily resolvable. We conclude that the Ci 40's resolution is more than adequate for CAD and GIS applications demanding fine line detail.

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