possible to edit Gerber silkscreen file?

[WhiteFireDragon]

I have an open source PCB file where all the layers were exported to 6 different Gerber files for production. I would like to modify just the silkscreen to add a little artwork and customization. If this possible, what free software should I use?

I know it would be a lot easier to change the original file in the PCB design software then export again into all the Gerber layers, however I don't have access to the original file. Please let me know if there are alternatives.

[IconicPCB]

Some PCB design software allows for gerber importation and conversion to cad format whihc can then be edited as per usual within cad package.
Otherwise You need a gerber editor. I am not aware of a free editor. I do however own Graphicode Powerstation a gerber cam station capable of editing gerber layer.

[WhiteFireDragon]

Some PCB design software allows for gerber importation and conversion to cad format whihc can then be edited as per usual within cad package.
Otherwise You need a gerber editor. I am not aware of a free editor. I do however own Graphicode Powerstation a gerber cam station capable of editing gerber layer.

Can you recommend any software that will allow this? Either the PCB design software, or gerber editor. If no free version, I'm willing to pay for a license, as long as it's not too expensive. I can't justify high cost for just editing text once or twice 

[free_electron]

afaik there are no free gerber editors.
But : her eis a workaround :

download a free cad tool ( like circuitmaker from altium )

draw your artwork on the silkscreen layer. spit out gerber
then MERGE the two gerber files.

you need to take a look in the original gerber file at the header and make sure you produce gerber with those settings.
then copy the aperture datablock and the artwork datablock over.

you can check all went well by opening your merged file with a gerber viewer.

[IconicPCB]

Another option... generate arwork in DXF format, email me the DXF and I shall output a gerber layer.
Do not forget to anotate dimensions on the DXF.