whachas think?
really nifty underground sea...
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really nifty underground sea...
whachas think?
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Plastered_Dragon
- Librarities Legend
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- Joined: Sun Jan 29, 2006 5:25 am
- Location: Fitchburg, MA
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hammr7
- Librarities Legend
- Posts: 698
- Joined: Wed Feb 11, 2004 11:29 pm
- Location: Southern New Jersey
The back sort of looks like it came into contact with some solvent. It was possibly handled by someone who had some sort of solvent (MEK?) on the fingertips of gloves that redisolved the ink on the back. Or possibly a problem with the printing problem allowed some ink to get on the sheet back.
If either is true, the sheet this card was in might have been on the printing press when a color station ran out of ink, or when some sort of print anomaly was being cleaned and corrected.
When cards sheets are printed, they are squeezed up against the ink (typically rotogravure) cyllinder with a rubber-coated nip cylinder to facilitate accurate handling of the cardstock and complete and uniform transfer of ink. Typically, the bottom of the ink cylinder sits in a tray of the ink. As the ink cylinder rotates, it picks up ink, passes a knife edge that wipes off any excess ink, then passes into the nip point where it contacts the cardstock and transfers ink.
When everything is running smoothly, ink is applied to the cardstock surface only. When a station runs out of ink, everything continues to run but at some point ink is no longer transfered. The ink stoppage does not show up as a perfect horizontal line, but as something like what the front of the card shows. However, this wouldn't explain the back.
When there is a printing problem (streaks, blobs, dried ink buildup on the outsides of the nip roll, etc.) that becomes major, the backing roll is released to allow press operators access to areas that must be cleaned. In modern presses, if any part of the machine is stopped all the backing rolls release. This causes the front side of the sheets in each station to lose contact with the ink cylinders. This would also explain the front losing color.
The sheets in the press at the time of a shutdown are usually pulled. If the worker had been cleaning the press, his gloves might still have traces of cleaning solvent on them, or some ink residue that contains solvent. His handling the backs of the sheets could cause the mottled look. Similarly, if the problem was a paper break that allowed some ink to transfer to the backing roll, or if a knife edge somehow loosened and allowed a print cylinder to flood ink onto the cardstock, then some ink could end up on the back of the cardstock, which would smear the ink there. Since the back colors are already dark composiites, you might not notice the other colors.
These possibilities could be confirmed by looking at the card back through a low power microscope or a strong magnifying glass, to see if the dot pattern was smeared. My guess is that the front would look fine, except possibly right at the point where color is lost.
If either is true, the sheet this card was in might have been on the printing press when a color station ran out of ink, or when some sort of print anomaly was being cleaned and corrected.
When cards sheets are printed, they are squeezed up against the ink (typically rotogravure) cyllinder with a rubber-coated nip cylinder to facilitate accurate handling of the cardstock and complete and uniform transfer of ink. Typically, the bottom of the ink cylinder sits in a tray of the ink. As the ink cylinder rotates, it picks up ink, passes a knife edge that wipes off any excess ink, then passes into the nip point where it contacts the cardstock and transfers ink.
When everything is running smoothly, ink is applied to the cardstock surface only. When a station runs out of ink, everything continues to run but at some point ink is no longer transfered. The ink stoppage does not show up as a perfect horizontal line, but as something like what the front of the card shows. However, this wouldn't explain the back.
When there is a printing problem (streaks, blobs, dried ink buildup on the outsides of the nip roll, etc.) that becomes major, the backing roll is released to allow press operators access to areas that must be cleaned. In modern presses, if any part of the machine is stopped all the backing rolls release. This causes the front side of the sheets in each station to lose contact with the ink cylinders. This would also explain the front losing color.
The sheets in the press at the time of a shutdown are usually pulled. If the worker had been cleaning the press, his gloves might still have traces of cleaning solvent on them, or some ink residue that contains solvent. His handling the backs of the sheets could cause the mottled look. Similarly, if the problem was a paper break that allowed some ink to transfer to the backing roll, or if a knife edge somehow loosened and allowed a print cylinder to flood ink onto the cardstock, then some ink could end up on the back of the cardstock, which would smear the ink there. Since the back colors are already dark composiites, you might not notice the other colors.
These possibilities could be confirmed by looking at the card back through a low power microscope or a strong magnifying glass, to see if the dot pattern was smeared. My guess is that the front would look fine, except possibly right at the point where color is lost.
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