Plate Densitometers

[Ben Cruise]

Hi would anybody be able to suggest a good plate densitometer,as i only seem to be able to find X-Rite iCPlate II. I am running FujiFilm LP-NV plates using a UV laser, if that makes any difference.

[larrysison]

You may also want to look into Techkon's SpectroPlate.. It's a great tool to measure plates and you can also use it to investigate press problems like doubling, slur, etc.

[maxon]

Or Betascreen ultradottie for that matter, a tad less expensive. We use a basic-plus model.

[JRomano]

Id like to second the Techkon SpectroPlate, Very easy to use and can be use for conventional and stochastic dot reading. Very stabil device and fast readings....Love to own one my self !


John

[BOB LESLIE]

Perfect timing.....
Centurfax have just released their NEW plate dotmeter (densitometer if you like)... EasyDot

Centurfax was of course the original and world-leader in these devices until they sold their Award Winning, CCDot to Xrite (the rest being history.....).

we are currently in discussion to set up USA distribution, but you can always contact me direct bob.leslie@Centurfax.co.uk....

Best regards

[marathon4ever]

You may also want to try the LithoCAM II or the AccuDot from Ihara...Ihara U.S., Inc. | Color Control Solutions for the Graphic Arts Industry. Good luck.

[nycku]

X-RITE Spectrodensitometer 500 series most accurate. we tried most of them and this is best one around.

[BOB LESLIE]

Interesting, you are right in many ways... a poor quality dotmeter will not be as good as good quality densi - but a good dotmeter will always provide superior results (that is why even Xrite promote dotmeter over densi for platereading)... sadly there are a few manufacturers that have provided inferior products - poor optics, poor lighting, mechanical failings, etc. - hopefully these are now being weaned out of the market.

Another point worth considering in this debate is "flexibility" - there are a number of units that require connection to a PC - tethered, this great reduces your ability to move around the plate or press room to take readings - standalone is definitely the way to go.

Also auto-cal - you dont want to have to worry about setting "black and white" readings before checking your plate (you still need to do this with a densi I believe, but stand to be corrected) - these "base" patches may not always be available on every plate.

All in my humble opinion and I stand to be corrected :-)

[ljgoldberg]

To those new to this discussion let me offer the following clarification;
A dotmeter is an image analysis device used to determine effective halftone dot area and provide a magnified image of the sample. On more capable models screen ruling, screen angle, and dot diameter are also calculated and displayed. Conventional (AM) screening and stochastic (FM) screening can be measured on many instruments. Continuous tone and color density is not measured with these devices.

Because dotmeters determine the actual dot size and geometry, their measurements are called "mechanical dot area" and will be in excellent agreement with any TIFF reader values. Differences between the TIFF value and the plate are due to the exposure and processing and are an accurate method to verify the stability of the process. They do not need any mathematical adjustment or 'n' factor. The UltraDottie II series from Beta Industries is offered in different configurations to satisfy the requirements of any workflow. Details can be seen here: Beta Ultra Dottie 2

Densitometers don't "know" or care what they are measuring, only offering information about the average reflectance of the sample. Spectral data or colorimetric data provides no greater accuracy or benefit over simple density data. The measured value is NOT the same as the true mechanical dot area and will not be in agreement with the TIFF value. Any densitometer that is stable and repeatable will tell you when the reflectance of the plate has changed but the reading will not be the true dot area.

Densitometer illumination systems have to be carefully designed to avoid sensitivity to directional effects in the aluminum substrate. If different results are reported depending upon the orientation of the instrument, then another complication has to be dealt with by the operator. The best illumination system for plate densitometers uses 360 degree illumination to eliminate directional sensitivity. The Platemaster from Beta Industries offered such an illumination arrangement. Now discontinued, it is supplanted by the UltraDottie II line.

All dotmeters and densitometers need a visible image of suitable contrast to produce accurate measurements. If you cannot see the image you cannot measure it. Various techniques to stain the image, manually develop it, or otherwise increase the contrast may be required. Dotmeters are available with multi-colored light sources to optimize the contrast of the image.

Dotmeters can also be supplied with traceable, absolute, dot area calibration standards. The Beta UltraDottie II, also sold as the X-Rite icPlate, comes with a chrome-on-glass target and a calibration database. ISO-registration management is greatly simplified, as well as superior inter-instrument agreement. Geographically distant plants can produce identical plates with solid data to back them up.

Larry Goldberg
Technical Director
Beta Industries
80-272-7336
Color Densitometers, CTP Calibration Systems for Print Quality

[RGPW17100]

When we went G7 we compared our xrite 528 to an actual plate reader and the 528 was not even close to what the actual dot was. If you need to read plate dots you really need to get a device specific to that. We purchased an xrite plate reader for under 2 k but I will have to go to work to get that device number.