Holla,

Recently I installed Feurio and scanned the ATIP info for some of my CDRs (before I was doing that by CDRidentifier) and I noticed a line that confused me a bit - "Indicative target writing power". I noticed that some new CDR (which Minmal recording speed is 2x) have this value equal to 4, whilst for some older ones this value is 5.
Does anybody know whether this parameter is somehow related to the (preferable) writing speed or it is related to dye type?
I made some search by keywords but didn't find some useble info, so every speculation would be appreciated

10x

http://www.cdrfaq.org/faq04.html#S4-13

I've been told by Andre Wiethoff that the burner ignores the target writing power in the ATIP and performs its own calibration. It makes sense, since the ATIP stampers can be sold from a manufacturer to another, who will then produce CDRs with wrong ATIPs.

From what I know, the target writing power is a laser output power multiplier that should indicate a nearly-correct power output for burners with no or insufficient power calibration to ensure that a "marginal" disc can be written at least (regarding BLER rates) even if the disc id is not present in the drive's firmware.

Today's modern burners perform a general power calibration before the write process in a dedicated disc area and, additionally, use a running OPC circuit which means they are able to vary their power output "on-the-fly" to ensure that changes in media quality over the disc radius can be taken into account.

Thank you Pio2001 for the useful link!

@JeanLuc: As follows from your post and from the information in the link above, the drive should use different output power depenging on the burning speed. Hence there should be no difference in the quality if 1x or 2x or 4x etc. is used. However I sometimes notice visual differencies of the colour of the burned sessions with some multisession CDR if different burning speeds are used. Does it mean that the burner does not adjust the output power according to the speed or burning or this is an effect of the uneven dye layer? Or maybe because of the aging of the dye layer between sessions?

No, I probably confused something ... normally, burning at higher speeds requires higher power output so the target writing power must be related to some kind of matrix which incorporates power values for all supported writing speeds - the target writing power is then used to fine-tune the power output as stated above.

But perhaps you can get some more information from an optical disc drive specialist ...

I get different colors from different speeds too. I got it burning two sessions in a row at different speeds, so aging is not the cause. The burning must be different, just because of the speed, even of the write power is adjusted.
The media rects differently to a long weak laser shot, than to a short strong one.