Scanner light sources- LED versus Cold cathode

Started 2 months ago | Discussions thread
Overrank Senior Member • Posts: 2,052
Re: Scanner light sources- LED versus Cold cathode

davesurrey wrote:

Sorry for another scanner question but...

Does anyone known if the LED light source of the Epson V800/850 makes any noticeable difference from the Cold Cathode source of the V700/750. Apart that is from the much faster "warm up" time.

Or to put it another way which has an emitted spectrum that will be more suitable for scanning negative 120 and 4x5 film?

Try “Evaluation of a LED-based flatbed document scanner for radiochromic film dosimetry in transmission mode” ( ). This is in the context of radiochromic film dosimetry but they extensive comparisons of the LED in a V800 with the CCFL in a 11000XL.

The conclusion is that “In overall, the performance of the LED document scanner is comparable to that of a cold cathode fluorescent lamp (CCFL). There are important spectral differences between LED and CCFL lamps that results in a higher sensitivity of the LED scanner in the green channel.” and that “the LED based scanner has a strong non-uniform response that must be adequately corrected for the measurement of dose distributions” but they mention that the V750 has a non-uniform response which seems to be more to do with the optics than the light source.

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