Have you checked your alcohol? Almost nobody does but you should every time you open a new container. There are three checks to perform, one requires a hydrometer centered on a specific gravity reading of 0.8. The specific gravity of IPA is .790; if you measure the gravity of your alcohol and it is higher than this, the alcohol is diluted with water. Some suppliers dilute the product as much as twenty percent because they are sure you will not test it. The other two tests are based on mixing some alcohol with water at a ratio of about half and half. This mixture should immediately form a clear solution, it should not be the least bit cloudy or hazy. If it is cloudy or hazy, it is likely contaminated with petroleum distillate which will seriously interfere with your printing. The last test is to shake this mixture vigorously. You should not be able to form any bubbles. If you can generate any foam at all, the alcohol is contaminated with some form of surfactant. If your alcohol fails any of these three tests, do not use it and it should be returned to whomever sold it to you.