(Quoted from Alan Howe and Impressions Magazine. Full article here.)

One type of emulsion may work for one shop, but not another. Why? The truth is that all emulsions from quality manufacturers work, but shops often use the wrong product for a particular type of printing. For example, if you are printing with the water-based ink and don't use an emulsion designed specifically for it, you may run into trouble. It's an easy fix: Simply switch out the product for a more suitable emulsion. More commonly, however, it's a failure in process that leads to error and makes it impossible for a stencil to work properly. It's often small or overlooked tasks that when fixed or tweaked can make all the difference. 

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