Operation Multigrade 500

william5 · 2006-05-28T21:59:08+00:00

Wer hat Erfahrung mit dem Multigradekopf 500 von Ilford. Ich habe leider nur eine Bedienungsanleitung in französisch und eine deutsche, die jedoch für das Na...

william5

Does anyone have any experience with the Ilford Multigrade Head 500? Unfortunately, I only have a user manual in French and a German one, but the latter is for the successor model. My problem: When determining the exposure time (‘AUTO’) using the light meter, it gives different results depending on which gradient is set. In my opinion, however, this should not be the case, as the device is specifically designed so that the exposure time remains constant across all gradients. I cannot find any indication in the instruction manuals that any particular gradient needs to be taken into account or set when taking a reading.

FrankJBeckmann

Hi Jens, Don’t worry, you’ve simply confirmed through practical testing what has already been discussed many times in various forums. A consistent exposure time cannot exist in such a universal sense as the advertising promises. That is only possible with exactly one batch of emulsion combined with exactly one developer at exactly one grey value. If anything deviates from that, exactly what you observed will happen.

william5

Hi Jens, Don’t worry, you’ve simply confirmed through practical testing what has already been discussed many times in various forums. A consistent exposure time cannot exist in such a blanket manner as the advertising promises. That is only possible with exactly one batch of emulsion in combination with exactly one developer at exactly one grey value. If anything deviates from that, exactly what you observed happens.

Hello Frank, That may be true in general, but in this case I see it differently. The whole process works as follows: The measurement is taken under neutral, white light. So the gradient cannot have an effect to that extent. Only the gradient setting on the control panel affects the calculation of the exposure value by the control unit. But that doesn’t make sense if the manufacturer states that the exposure time should remain the same. I also find it surprising because the user manual doesn’t mention a word about the desired gradation that needs to be set in parallel when discussing the measurement. Otherwise, I can certainly imagine that at least an approximately equal exposure time is possible for both #0 and #5. Initial tests have at least confirmed this for me. It may well be that things are different with the next type of paper. But the device offers the possibility of calibration thanks to the separate control of the two (!) lamps per filter. In the calibration process, the mid-grey value is taken as the basis. So far, it all makes sense to me... it’s just the measurement that’s causing problems.

FrankJBeckmann

Hi Jens, I haven’t quite understood you yet. You place the measuring probe on the base plate and measure the exposure time under white light. And when does this value change?

william5

Hello Frank, Yes, I place the probe on the base plate and measure the brightest spot that is still just visible. The control unit has an ‘Auto’ button for the measurement function. This adjusts the lamps for both filters to the same brightness level (let’s say white light). Then you position the probe and press the measurement button. The device then switches off the light and measures the ambient light for about two seconds (so that this is taken into account when calculating the reading) and calculates the exposure time. The calculated value now varies depending on the set gradient. Example: #0 gives 7 s and #5 gives 1.4 s. Regards, Jens It just strikes me that the exposure times in relation to the filter or the gradient value aren’t entirely consistent either. Here, the device calculates a significantly shorter value for the soft gradient than for the hard gradient. Isn’t it actually the case that longer exposure times are required for #5 than for soft?

FrankJBeckmann

Hi Jens, That makes more sense now. You’ve calibrated the device to mid-grey, but you’re measuring the brightest area that’s just about to show detail. If the time for the mid-grey is to remain the same, then naturally the time for the brightest area changes with the gradient. If it were to remain the same, then the time for the mid-grey would change with the gradient, but that’s precisely what we don’t want to happen. Whether a paper is more sensitive at the soft or hard end depends solely on the type. What you mean is the usual advice for filter foils that you should double the exposure time for hard gradients. However, this isn’t down to the paper; rather, the foils for hard gradients simply let through less light than the other foils.