# Bandpass filters **URL:** \ **Category:** General\ **Created:** [16 October 2022 13:42 UTC](https://openflexure.discourse.group/t/bandpass-filters/1059 "2022-10-16T13:42:36Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![srehman](https://avatars.discourse-cdn.com/v4/letter/s/f4b2a3/32.png) [@srehman](https://openflexure.discourse.group/u/srehman)\ **Post date:** [16 October 2022 13:42 UTC](https://openflexure.discourse.group/t/bandpass-filters/1059/1 "2022-10-16T13:42:36Z")
Hi there, I have been working on making the Delta Stage (transmission) for fluorescent imaging. Was hoping someone could please advise on where the best place to get bandpass filters would be? I have the LEDs of the wavelegnth I need for excitation of my fluorescently labelled samples but can’t seem to find a good source for buying emission filters. I am working with commonly used fluorophores (eg Hoechst Ex/Em 350/461 nm; Fluorescein Ex/Em 488/516 nm; Rhodamine Ex/Em 546/568 nm; Cell tracker red Ex/Em 577/602 nm and SulphoCy5 Ex/Em 649/670 nm). Any and all help is appreciated. Cheers SR ---
**Author:** ![r.w.bowman](https://yyz2.discourse-cdn.com/free1/user_avatar/openflexure.discourse.group/r.w.bowman/32/15_2.png) [@r.w.bowman](https://openflexure.discourse.group/u/r.w.bowman)\ **Post date:** [17 October 2022 16:14 UTC](https://openflexure.discourse.group/t/bandpass-filters/1059/2 "2022-10-17T16:14:20Z")
Hi @srehman nice to hear from you! I used to always recommend Comar, but they are getting less good for small orders. ThorLabs is my usual go-to, but there are many companies selling them such as Chroma, Edmund Optics, and many more specialist suppliers. Usually they’ll sell the filters separately, so you’d need to pick a 45 degree dichroic (remembering that interference filters are usually angle-dependent: usually they will tell you the wavelength at 45 degrees and normal incidence), plus excitation/emission filters (at normal incidence). Are you happy with what you’d need from each filter? I don’t think there’s much OpenFlexure documentation about how to choose filters, but there ought to be something good on e.g. MicroscopyU, and if anyone knows a good link I should add it to the documentation somewhere…