Earlier this month I was visiting a customer who utilizes multiple ColorMetrix licenses to monitor and control; plate making; proofing; and pressroom. Several years ago this customer used ColorMetrix in his plate making operation to uncover a processor replenishment problem that not even the plate vendor was able to unravel. During this visit, he told me about a recent experience involving a pressman who came to him asking for a new plate so that he could achieve a match on press. For some reason he could not get the cyan to fall in appropriately. My customer consulted his ColorMetrix plate database and confirmed that the plate was properly made. He then measured a press sheet provided by the pressman and compared it to his historical data for that press and paper combination. The cyan dot gain (TVI) was about 10 points away from the expected values.
He agreed to make a new plate with an adjusted curve in the interest of getting the job off press with acceptable color, but also suggested the pressman take a long hard look at the cyan printing unit. Before the plate was even processed the pressman returned and said to never mind he had uncovered a roller problem in the cyan unit.
Yes, all the data collection our client does takes time and effort, but what is an hour of your press time worth? He pointed out that this is not an isolated occurrence. Just having a densitometer and measuring density and dot gain would have done no good in this situation. My customer and his pressman needed to know what the expected density and dot gain would be on the press and paper combination being run.
By simply measuring the OK sheet from most jobs, within 30 days you will have a very substantial database to fall back on when problems like the one illustrated above occur. So, process control is not free, but instead an investment with a fairly easy to calculate return. There are more examples of how process control has saved our clients money at here at JimRaffel.com, so feel free to read the archives.