your nozzle check looks pretty clean , and without irregularities of the height of the staircase steps.
Do you see a difference between different quality settings ?
Your printer is pretty old - does the driver give you a 'microweave' option which Epson was offering for quite a while on photoprinters e.g. on the R800 or R265 ?
Do you see a difference when you use different papers - photo or matte papers when printing a photo ?
Did you do a printhead alignment recently ?
Since when do you observe the tiny white gaps - e.g. suddenly or after a particular problem ?
thanks for your input. One thing i have noticed is the media setting is on "plain paper" and I cannot get it to switch to another media setting....I used enhanced matte paper and I have used plain paper...the horizontal lines show up on both prints