Re: Gum calibration (was: Paper negatives- Ink Selection)
Hi Mark, thanks for chiming in. See the end of the message... 18 Ekim 2008, Cumartesi, 10:51 pm tarihinde, ender100 yazmış: > > ... the density range of the negative does not affect the exposure. > Exposure is still merely dependent upon the UV density of the substrate > you are printing on. Once the exposure is determined, then you just match > the density range of the negative to the exposure scale of the contrast > mix you are using. If, for some reason you have a fixed density range in > the negative, say from using all inks to make a "grayscale negative", then > you must alter the contrast mix so that its exposure scale matches the > density range of the negative. If you end up with a density range that is > too high, your highlights will be blown out. However, if you try to bring > tone into the highlights by increasing exposure, you end up over exposing > the shadows and blocking them up. What should be done in this case is to > either increase the exposure scale of the contrast mix (by adding more > chromate) to match the negative or reduce the density range of the > negative, as you have suggested, to match the exposure scale of the > contrast mix. Very true... But ideally. (Assuming the worker is doing it according to the ideal.) If you're not doing it according to the ideal (such as: not using a process adjustment curve - or any other means to translate linear source image tones to the characteristic curve of the target process - to start with...), then the practical consequence would be DR affecting the exposure, because you'll naturally expose for the highlights (since nobody will be interested in a print with blown highlights, with in-negative-midtones converted to in-print-highligts), and live with shadows that you get. This is my opinion on what is probably happening here... Thanks again, Loris.
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