by clicking the arrows at the side of the page, or by using the toolbar.
by clicking anywhere on the page.
by dragging the page around when zoomed in.
by clicking anywhere on the page when zoomed in.
web sites or send emails by clicking on hyperlinks.
Email this page to a friend
Search this issue
Index - jump to page or section
Archive - view past issues
FLEXO Magazine : July 2007
These targets are used for determination of achievable line thicknesses. The information from these targets will be used to determine the absolute minimum line, both positive and reverse, that can be achieved when printing versus what may appear on screen. What to look for: The positive and reverse lines are broken in the centers to observe the effects of gain. Ideally the lines should appear of similar width when printed correctly. This target is used to define the minimum positive and reverse type sizes which can be satisfactorily held by the plate. It contains positive and reverse type in both serif and sans serif styles in 1,2,3,4,5,6,8, 10,12,14,16,&18 point sizes. Used to determine the smallest line that can be held by the plate. Also used to examine the amount of shoulder produced to support the lines. What to look for: Examine the shoulder and face of the lines. Even the thinnest of the lines should have a flat face supported by a defined shoulder. The reason for the multiple copies of the four- square highlight dot target is to reveal the minimum solid dot held by the plate. Many of these targets are placed in various locations on the test page to ensure you are getting even exposure and even washout across the plate. Type Printability Target Grayscale Target Line Printability Minimum Dot Target Vignette Target What to look for in positive type areas: Check to see that the shoulders of the smallest positive type are adequately developed. The surface of the type should be flat. There should be visible polymer buildup between the letters. What to look for in reverse type areas: The inside of the text should be etched deeply into the polymer, often exposing the plate in large open letters. You should see a slight polymer buildup inside the open letter around the edges.The printing surface around the reverse type should be smooth and flat. Resolution Target This target is to demonstrate the plate’s ability to hold a smooth gradient as the dot goes from solid 100 percent to zero percent, or no dot. What to look for: Examine the target concentrating on the highlight end of the vignette to determine the ability of the dots to go from a 100% to 0% dots. The goal is to make the smoothest transition possible without a harsh break between the diminishing dot sizes. What to look for in the 2% square: Due to the limitations on a flexo plate’s ability to retain it’s highlight dots through the washout cycle, the polymer inside the 2% square will be completely removed and only the plate surface will be seen. What to look for in the 3% square: The 3% square should still be holding 50%- 75% of its dots with some small noticeable areas where the bare plate will show through. Many of the dots will be laying on their sides but most will be standing upright. The dots in the 3% square may or may not print depending on the strength of the shoulders. What to look for in the 4% square: The 4% square is expected to hold and print 100% of its dots with all of the dots standing straight. This is the smallest full highlight dot that the plate should be capable of carrying. What to look for in the 5% square: The dots in the 5% square should have a slight- ly fatter shoulder than the dots held by the 4% square. The plate should have no problems carrying all of the 5% dots. The four multistep scales are used in two ways. One is to see what minimum and maximum dot size you are carrying and the other is to see if you are getting the same results on all outer edges of the plate. Varying results would indicate exposure problems or developing problems. What to look for in shadow area: Using a loupe, search for the highest density percentage in the shadow area that is still holding a dot. This should be the 95% block or greater. What to look for in midtones: Check the formation of the 50% block for the checkerboard appearance. You should notice that the squares of polymer are equal in size to the squares that have been washed out. Target What to look for in midtones: Check the four grayscale targets to make sure you are holding a solid 4% breaking out in the 3% square (see “Minimum Dot Target” section). Compare your highlight dots in all four locations to be sure you are getting an identical reproduction on all sides of the plate. Lindsay Limbaugh Lindsay Limbaugh Quality Control Supervisor Chattanooga Times Free Press w w w . f l e x o g r a p h y . o r g J U LY 2 0 0 7 F L E X O 2 9
Golden Anniversary Commemorative Journal